LeetCode
Author: github.com/lzl124631x
My C++ Code for LeetCode OJ.
Please give this repo a
Now I'm using a Chrome Extension I developed -- LeetCoder -- to facilitate my having fun on LeetCode. Features including but not limited to:
- showing stats
- copying problem, answer and testcases
- randomly picking a problem.
| # | Title | Difficulty | Solution |
|---|---|---|---|
| 1 | Two Sum | Easy | Solution |
| 2 | Add Two Numbers | Medium | Solution |
| 3 | Longest Substring Without Repeating Characters | Medium | Solution |
| 4 | Median of Two Sorted Arrays | Hard | Solution |
| 5 | Longest Palindromic Substring | Medium | Solution |
| 6 | ZigZag Conversion | Medium | Solution |
| 7 | Reverse Integer | Easy | Solution |
| 8 | String to Integer (atoi) | Medium | Solution |
| 9 | Palindrome Number | Easy | Solution |
| 10 | Regular Expression Matching | Hard | Solution |
| 11 | Container With Most Water | Medium | Solution |
| 12 | Integer to Roman | Medium | Solution |
| 13 | Roman to Integer | Easy | Solution |
| 14 | Longest Common Prefix | Easy | Solution |
| 15 | 3Sum | Medium | Solution |
| 16 | 3Sum Closest | Medium | Solution |
| 17 | Letter Combinations of a Phone Number | Medium | Solution |
| 18 | 4Sum | Medium | Solution |
| 19 | Remove Nth Node From End of List | Medium | Solution |
| 20 | Valid Parentheses | Easy | Solution |
| 21 | Merge Two Sorted Lists | Easy | Solution |
| 22 | Generate Parentheses | Medium | Solution |
| 23 | Merge k Sorted Lists | Hard | Solution |
| 24 | Swap Nodes in Pairs | Medium | Solution |
| 25 | Reverse Nodes in k-Group | Hard | Solution |
| 26 | Remove Duplicates from Sorted Array | Easy | Solution |
| 27 | Remove Element | Easy | Solution |
| 28 | Implement strStr() | Easy | Solution |
| 29 | Divide Two Integers | Medium | Solution |
| 30 | Substring with Concatenation of All Words | Hard | Solution |
| 31 | Next Permutation | Medium | Solution |
| 32 | Longest Valid Parentheses | Hard | Solution |
| 33 | Search in Rotated Sorted Array | Medium | Solution |
| 34 | Find First and Last Position of Element in Sorted Array | Medium | Solution |
| 35 | Search Insert Position | Easy | Solution |
| 36 | Valid Sudoku | Medium | Solution |
| 37 | Sudoku Solver | Hard | Solution |
| 38 | Count and Say | Medium | Solution |
| 39 | Combination Sum | Medium | Solution |
| 40 | Combination Sum II | Medium | Solution |
| 41 | First Missing Positive | Hard | Solution |
| 42 | Trapping Rain Water | Hard | Solution |
| 43 | Multiply Strings | Medium | Solution |
| 44 | Wildcard Matching | Hard | Solution |
| 45 | Jump Game II | Medium | Solution |
| 46 | Permutations | Medium | Solution |
| 47 | Permutations II | Medium | Solution |
| 48 | Rotate Image | Medium | Solution |
| 49 | Group Anagrams | Medium | Solution |
| 50 | Pow(x, n) | Medium | Solution |
| 51 | N-Queens | Hard | Solution |
| 52 | N-Queens II | Hard | Solution |
| 53 | Maximum Subarray | Easy | Solution |
| 54 | Spiral Matrix | Medium | Solution |
| 55 | Jump Game | Medium | Solution |
| 56 | Merge Intervals | Medium | Solution |
| 57 | Insert Interval | Hard | Solution |
| 58 | Length of Last Word | Easy | Solution |
| 59 | Spiral Matrix II | Medium | Solution |
| 60 | Permutation Sequence | Hard | Solution |
| 61 | Rotate List | Medium | Solution |
| 62 | Unique Paths | Medium | Solution |
| 63 | Unique Paths II | Medium | Solution |
| 64 | Minimum Path Sum | Medium | Solution |
| 65 | Valid Number | Hard | Solution |
| 66 | Plus One | Easy | Solution |
| 67 | Add Binary | Easy | Solution |
| 68 | Text Justification | Hard | Solution |
| 69 | Sqrt(x) | Easy | Solution |
| 70 | Climbing Stairs | Easy | Solution |
| 71 | Simplify Path | Medium | Solution |
| 72 | Edit Distance | Hard | Solution |
| 73 | Set Matrix Zeroes | Medium | Solution |
| 74 | Search a 2D Matrix | Medium | Solution |
| 75 | Sort Colors | Medium | Solution |
| 76 | Minimum Window Substring | Hard | Solution |
| 77 | Combinations | Medium | Solution |
| 78 | Subsets | Medium | Solution |
| 79 | Word Search | Medium | Solution |
| 80 | Remove Duplicates from Sorted Array II | Medium | Solution |
| 81 | Search in Rotated Sorted Array II | Medium | Solution |
| 82 | Remove Duplicates from Sorted List II | Medium | Solution |
| 83 | Remove Duplicates from Sorted List | Solution | |
| 84 | Largest Rectangle in Histogram | Hard | Solution |
| 85 | Maximal Rectangle | Hard | Solution |
| 86 | Partition List | Medium | Solution |
| 87 | Scramble String | Hard | Solution |
| 88 | Merge Sorted Array | Easy | Solution |
| 89 | Gray Code | Medium | Solution |
| 90 | Subsets II | Medium | Solution |
| 91 | Decode Ways | Medium | Solution |
| 92 | Reverse Linked List II | Medium | Solution |
| 93 | Restore IP Addresses | Solution | |
| 94 | Binary Tree Inorder Traversal | Easy | Solution |
| 95 | Unique Binary Search Trees II | Medium | Solution |
| 96 | Unique Binary Search Trees | Medium | Solution |
| 97 | Interleaving String | Hard | Solution |
| 98 | Validate Binary Search Tree | Medium | Solution |
| 99 | Recover Binary Search Tree | Hard | Solution |
| 100 | Same Tree | Easy | Solution |
| 101 | Symmetric Tree | Solution | |
| 102 | Binary Tree Level Order Traversal | Medium | Solution |
| 103 | Binary Tree Zigzag Level Order Traversal | Medium | Solution |
| 104 | Maximum Depth of Binary Tree | Easy | Solution |
| 106 | Construct Binary Tree from Inorder and Postorder Traversal | Medium | Solution |
| 107 | Binary Tree Level Order Traversal II | Medium | Solution |
| 108 | Convert Sorted Array to Binary Search Tree | Easy | Solution |
| 109 | Convert Sorted List to Binary Search Tree | Medium | Solution |
| 110 | Balanced Binary Tree | Easy | Solution |
| 111 | Minimum Depth of Binary Tree | Easy | Solution |
| 112 | Path Sum | Easy | Solution |
| 113 | Path Sum II | Medium | Solution |
| 114 | Flatten Binary Tree to Linked List | Medium | Solution |
| 115 | Distinct Subsequences | Hard | Solution |
| 116 | Populating Next Right Pointers in Each Node | Medium | Solution |
| 117 | Populating Next Right Pointers in Each Node II | Medium | Solution |
| 118 | Pascal's Triangle | Easy | Solution |
| 119 | Pascal's Triangle II | Easy | Solution |
| 120 | Triangle | Medium | Solution |
| 121 | Best Time to Buy and Sell Stock | Easy | Solution |
| 122 | Best Time to Buy and Sell Stock II | Easy | Solution |
| 123 | Best Time to Buy and Sell Stock III | Hard | Solution |
| 124 | Binary Tree Maximum Path Sum | Hard | Solution |
| 125 | Valid Palindrome | Easy | Solution |
| 126 | Word Ladder II | Hard | Solution |
| 127 | Word Ladder | Hard | Solution |
| 128 | Longest Consecutive Sequence | Hard | Solution |
| 129 | Sum Root to Leaf Numbers | Medium | Solution |
| 130 | Surrounded Regions | Medium | Solution |
| 131 | Palindrome Partitioning | Medium | Solution |
| 133 | Clone Graph | Medium | Solution |
| 134 | Gas Station | Medium | Solution |
| 135 | Candy | Hard | Solution |
| 136 | Single Number | Easy | Solution |
| 137 | Single Number II | Medium | Solution |
| 138 | Copy List with Random Pointer | Medium | Solution |
| 139 | Word Break | Medium | Solution |
| 140 | Word Break II | Hard | Solution |
| 141 | Linked List Cycle | Easy | Solution |
| 142 | Linked List Cycle II | Medium | Solution |
| 143 | Reorder List | Medium | Solution |
| 144 | Binary Tree Preorder Traversal | Easy | Solution |
| 145 | Binary Tree Postorder Traversal | Easy | Solution |
| 146 | LRU Cache | Medium | Solution |
| 147 | Insertion Sort List | Medium | Solution |
| 148 | Sort List | Medium | Solution |
| 149 | Max Points on a Line | Hard | Solution |
| 150 | Evaluate Reverse Polish Notation | Medium | Solution |
| 151 | Reverse Words in a String | Medium | Solution |
| 152 | Maximum Product Subarray | Medium | Solution |
| 153 | Find Minimum in Rotated Sorted Array | Medium | Solution |
| 154 | Find Minimum in Rotated Sorted Array II | Hard | Solution |
| 155 | Min Stack | Easy | Solution |
| 156 | Binary Tree Upside Down | Medium | Solution |
| 157 | Read N Characters Given Read4 | Easy | Solution |
| 158 | Read N Characters Given Read4 II - Call multiple times | Hard | Solution |
| 159 | Longest Substring with At Most Two Distinct Characters | Medium | Solution |
| 160 | Intersection of Two Linked Lists | Easy | Solution |
| 161 | One Edit Distance | Medium | Solution |
| 162 | Find Peak Element | Medium | Solution |
| 163 | Missing Ranges | Easy | Solution |
| 164 | Maximum Gap | Hard | Solution |
| 165 | Compare Version Numbers | Medium | Solution |
| 166 | Fraction to Recurring Decimal | Solution | |
| 167 | Two Sum II - Input array is sorted | Solution | |
| 169 | Majority Element | Easy | Solution |
| 170 | Two Sum III - Data structure design | Easy | Solution |
| 171 | Excel Sheet Column Number | Easy | Solution |
| 173 | Binary Search Tree Iterator | Medium | Solution |
| 174 | Dungeon Game | Hard | Solution |
| 175 | Combine Two Tables | Easy | Solution |
| 176 | Second Highest Salary | Easy | Solution |
| 179 | Largest Number | Medium | Solution |
| 181 | Employees Earning More Than Their Managers | Easy | Solution |
| 182 | Duplicate Emails | Easy | Solution |
| 186 | Reverse Words in a String II | Medium | Solution |
| 187 | Repeated DNA Sequences | Solution | |
| 188 | Best Time to Buy and Sell Stock IV | Hard | Solution |
| 189 | Rotate Array | Medium | Solution |
| 190 | Reverse Bits | Easy | Solution |
| 191 | Number of 1 Bits | Easy | Solution |
| 195 | Tenth Line | Easy | Solution |
| 198 | House Robber | Medium | Solution |
| 199 | Binary Tree Right Side View | Medium | Solution |
| 200 | Number of Islands | Medium | Solution |
| 201 | Bitwise AND of Numbers Range | Medium | Solution |
| 202 | Happy Number | Easy | Solution |
| 203 | Remove Linked List Elements | Easy | Solution |
| 204 | Count Primes | Easy | Solution |
| 205 | Isomorphic Strings | Easy | Solution |
| 206 | Reverse Linked List | Easy | Solution |
| 207 | Course Schedule | Medium | Solution |
| 208 | Implement Trie (Prefix Tree) | Medium | Solution |
| 209 | Minimum Size Subarray Sum | Medium | Solution |
| 210 | Course Schedule II | Medium | Solution |
| 211 | Add and Search Word - Data structure design | Medium | Solution |
| 212 | Word Search II | Hard | Solution |
| 213 | House Robber II | Medium | Solution |
| 214 | Shortest Palindrome | Hard | Solution |
| 215 | Kth Largest Element in an Array | Medium | Solution |
| 216 | Combination Sum III | Medium | Solution |
| 217 | Contains Duplicate | Easy | Solution |
| 218 | The Skyline Problem | Hard | Solution |
| 219 | Contains Duplicate II | Easy | Solution |
| 220 | Contains Duplicate III | Medium | Solution |
| 221 | Maximal Square | Medium | Solution |
| 222 | Count Complete Tree Nodes | Medium | Solution |
| 223 | Rectangle Area | Solution | |
| 224 | Basic Calculator | Hard | Solution |
| 225 | Implement Stack using Queues | Easy | Solution |
| 226 | Invert Binary Tree | Easy | Solution |
| 227 | Basic Calculator II | Medium | Solution |
| 228 | Summary Ranges | Easy | Solution |
| 229 | Majority Element II | Solution | |
| 230 | Kth Smallest Element in a BST | Medium | Solution |
| 231 | Power of Two | Easy | Solution |
| 232 | Implement Queue using Stacks | Easy | Solution |
| 234 | Palindrome Linked List | Easy | Solution |
| 235 | Lowest Common Ancestor of a Binary Search Tree | Easy | Solution |
| 236 | Lowest Common Ancestor of a Binary Tree | Medium | Solution |
| 237 | Delete Node in a Linked List | Easy | Solution |
| 238 | Product of Array Except Self | Medium | Solution |
| 239 | Sliding Window Maximum | Hard | Solution |
| 240 | Search a 2D Matrix II | Medium | Solution |
| 241 | Different Ways to Add Parentheses | Medium | Solution |
| 242 | Valid Anagram | Easy | Solution |
| 243 | Shortest Word Distance | Easy | Solution |
| 244 | Shortest Word Distance II | Medium | Solution |
| 246 | Strobogrammatic Number | Easy | Solution |
| 247 | Strobogrammatic Number II | Medium | Solution |
| 249 | Group Shifted Strings | Medium | Solution |
| 250 | Count Univalue Subtrees | Medium | Solution |
| 251 | Flatten 2D Vector | Medium | Solution |
| 252 | Meeting Rooms | Easy | Solution |
| 253 | Meeting Rooms II | Medium | Solution |
| 255 | Verify Preorder Sequence in Binary Search Tree | Medium | Solution |
| 256 | Paint House | Easy | Solution |
| 257 | Binary Tree Paths | Easy | Solution |
| 258 | Add Digits | Easy | Solution |
| 259 | 3Sum Smaller | Medium | Solution |
| 260 | Single Number III | Medium | Solution |
| 261 | Graph Valid Tree | Medium | Solution |
| 263 | Ugly Number | Solution | |
| 264 | Ugly Number II | Medium | Solution |
| 266 | Palindrome Permutation | Easy | Solution |
| 268 | Missing Number | Easy | Solution |
| 269 | Alien Dictionary | Hard | Solution |
| 270 | Closest Binary Search Tree Value | Easy | Solution |
| 271 | Encode and Decode Strings | Medium | Solution |
| 273 | Integer to English Words | Hard | Solution |
| 274 | H-Index | Medium | Solution |
| 275 | H-Index II | Medium | Solution |
| 276 | Paint Fence | Medium | Solution |
| 277 | Find the Celebrity | Medium | Solution |
| 278 | First Bad Version | Easy | Solution |
| 279 | Perfect Squares | Medium | Solution |
| 280 | Wiggle Sort | Medium | Solution |
| 281 | Zigzag Iterator | Medium | Solution |
| 284 | Peeking Iterator | Medium | Solution |
| 285 | Inorder Successor in BST | Medium | Solution |
| 286 | Walls and Gates | Medium | Solution |
| 287 | Find the Duplicate Number | Medium | Solution |
| 289 | Game of Life | Medium | Solution |
| 290 | Word Pattern | Easy | Solution |
| 291 | Word Pattern II | Medium | Solution |
| 293 | Flip Game | Easy | Solution |
| 294 | Flip Game II | Medium | Solution |
| 295 | Find Median from Data Stream | Hard | Solution |
| 296 | Best Meeting Point | Hard | Solution |
| 297 | Serialize and Deserialize Binary Tree | Hard | Solution |
| 298 | Binary Tree Longest Consecutive Sequence | Medium | Solution |
| 299 | Bulls and Cows | Medium | Solution |
| 300 | Longest Increasing Subsequence | Medium | Solution |
| 301 | Remove Invalid Parentheses | Hard | Solution |
| 302 | Smallest Rectangle Enclosing Black Pixels | Hard | Solution |
| 303 | Range Sum Query - Immutable | Solution | |
| 304 | Range Sum Query 2D - Immutable | Solution | |
| 307 | Range Sum Query - Mutable | Medium | Solution |
| 309 | Best Time to Buy and Sell Stock with Cooldown | Medium | Solution |
| 310 | Minimum Height Trees | Medium | Solution |
| 311 | Sparse Matrix Multiplication | Medium | Solution |
| 312 | Burst Balloons | Hard | Solution |
| 313 | Super Ugly Number | Solution | |
| 314 | Binary Tree Vertical Order Traversal | Medium | Solution |
| 315 | Count of Smaller Numbers After Self | Hard | Solution |
| 316 | Remove Duplicate Letters | Medium | Solution |
| 317 | Shortest Distance from All Buildings | Hard | Solution |
| 318 | Maximum Product of Word Lengths | Medium | Solution |
| 320 | Generalized Abbreviation | Medium | Solution |
| 321 | Create Maximum Number | Hard | Solution |
| 322 | Coin Change | Medium | Solution |
| 323 | Number of Connected Components in an Undirected Graph | Medium | Solution |
| 324 | Wiggle Sort II | Solution | |
| 325 | Maximum Size Subarray Sum Equals k | Medium | Solution |
| 326 | Power of Three | Easy | Solution |
| 327 | Count of Range Sum | Hard | Solution |
| 328 | Odd Even Linked List | Easy | Solution |
| 329 | Longest Increasing Path in a Matrix | Hard | Solution |
| 330 | Patching Array | Solution | |
| 331 | Verify Preorder Serialization of a Binary Tree | Solution | |
| 332 | Reconstruct Itinerary | Hard | Solution |
| 333 | Largest BST Subtree | Medium | Solution |
| 334 | Increasing Triplet Subsequence | Medium | Solution |
| 335 | Self Crossing | Solution | |
| 336 | Palindrome Pairs | Hard | Solution |
| 337 | House Robber III | Medium | Solution |
| 338 | Counting Bits | Easy | Solution |
| 339 | Nested List Weight Sum | Easy | Solution |
| 340 | Longest Substring with At Most K Distinct Characters | Hard | Solution |
| 341 | Flatten Nested List Iterator | Medium | Solution |
| 342 | Power of Four | Easy | Solution |
| 343 | Integer Break | Medium | Solution |
| 344 | Reverse String | Easy | Solution |
| 345 | Reverse Vowels of a String | Easy | Solution |
| 346 | Moving Average from Data Stream | Easy | Solution |
| 347 | Top K Frequent Elements | Medium | Solution |
| 348 | Design Tic-Tac-Toe | Medium | Solution |
| 349 | Intersection of Two Arrays | Easy | Solution |
| 350 | Intersection of Two Arrays II | Solution | |
| 352 | Data Stream as Disjoint Intervals | Solution | |
| 354 | Russian Doll Envelopes | Hard | Solution |
| 355 | Design Twitter | Medium | Solution |
| 357 | Count Numbers with Unique Digits | Solution | |
| 359 | Logger Rate Limiter | Easy | Solution |
| 360 | Sort Transformed Array | Medium | Solution |
| 361 | Bomb Enemy | Medium | Solution |
| 362 | Design Hit Counter | Medium | Solution |
| 363 | Max Sum of Rectangle No Larger Than K | Hard | Solution |
| 364 | Nested List Weight Sum II | Medium | Solution |
| 365 | Water and Jug Problem | Solution | |
| 366 | Find Leaves of Binary Tree | Medium | Solution |
| 367 | Valid Perfect Square | Easy | Solution |
| 368 | Largest Divisible Subset | Medium | Solution |
| 369 | Plus One Linked List | Medium | Solution |
| 370 | Range Addition | Medium | Solution |
| 371 | Sum of Two Integers | Medium | Solution |
| 372 | Super Pow | Solution | |
| 373 | Find K Pairs with Smallest Sums | Solution | |
| 374 | Guess Number Higher or Lower | Easy | Solution |
| 375 | Guess Number Higher or Lower II | Medium | Solution |
| 376 | Wiggle Subsequence | Medium | Solution |
| 377 | Combination Sum IV | Medium | Solution |
| 378 | Kth Smallest Element in a Sorted Matrix | Medium | Solution |
| 379 | Design Phone Directory | Medium | Solution |
| 380 | Insert Delete GetRandom O(1) | Medium | Solution |
| 381 | Insert Delete GetRandom O(1) - Duplicates allowed | Hard | Solution |
| 382 | Linked List Random Node | Medium | Solution |
| 383 | Ransom Note | Easy | Solution |
| 384 | Shuffle an Array | Medium | Solution |
| 385 | Mini Parser | Medium | Solution |
| 386 | Lexicographical Numbers | Medium | Solution |
| 387 | First Unique Character in a String | Easy | Solution |
| 388 | Longest Absolute File Path | Medium | Solution |
| 389 | Find the Difference | Easy | Solution |
| 390 | Elimination Game | Solution | |
| 391 | Perfect Rectangle | Solution | |
| 392 | Is Subsequence | Easy | Solution |
| 393 | UTF-8 Validation | Solution | |
| 394 | Decode String | Medium | Solution |
| 395 | Longest Substring with At Least K Repeating Characters | Medium | Solution |
| 396 | Rotate Function | Medium | Solution |
| 397 | Integer Replacement | Solution | |
| 398 | Random Pick Index | Solution | |
| 399 | Evaluate Division | Medium | Solution |
| 400 | Nth Digit | Medium | Solution |
| 401 | Binary Watch | Solution | |
| 402 | Remove K Digits | Medium | Solution |
| 403 | Frog Jump | Hard | Solution |
| 404 | Sum of Left Leaves | Easy | Solution |
| 405 | Convert a Number to Hexadecimal | Solution | |
| 406 | Queue Reconstruction by Height | Medium | Solution |
| 407 | Trapping Rain Water II | Hard | Solution |
| 408 | Valid Word Abbreviation | Easy | Solution |
| 409 | Longest Palindrome | Easy | Solution |
| 410 | Split Array Largest Sum | Hard | Solution |
| 412 | Fizz Buzz | Easy | Solution |
| 413 | Arithmetic Slices | Medium | Solution |
| 414 | Third Maximum Number | Solution | |
| 415 | Add Strings | Easy | Solution |
| 416 | Partition Equal Subset Sum | Medium | Solution |
| 417 | Pacific Atlantic Water Flow | Medium | Solution |
| 418 | Sentence Screen Fitting | Medium | Solution |
| 419 | Battleships in a Board | Solution | |
| 420 | Strong Password Checker | Solution | |
| 421 | Maximum XOR of Two Numbers in an Array | Medium | Solution |
| 422 | Valid Word Square | Easy | Solution |
| 423 | Reconstruct Original Digits from English | Solution | |
| 424 | Longest Repeating Character Replacement | Medium | Solution |
| 425 | Word Squares | Hard | Solution |
| 426 | Convert Binary Search Tree to Sorted Doubly Linked List | Medium | Solution |
| 427 | Construct Quad Tree | Medium | Solution |
| 429 | N-ary Tree Level Order Traversal | Medium | Solution |
| 430 | Flatten a Multilevel Doubly Linked List | Medium | Solution |
| 431 | Encode N-ary Tree to Binary Tree | Hard | Solution |
| 432 | All O`one Data Structure | Solution | |
| 433 | Minimum Genetic Mutation | Medium | Solution |
| 434 | Number of Segments in a String | Solution | |
| 435 | Non-overlapping Intervals | Medium | Solution |
| 436 | Find Right Interval | Medium | Solution |
| 437 | Path Sum III | Medium | Solution |
| 438 | Find All Anagrams in a String | Medium | Solution |
| 439 | Ternary Expression Parser | Medium | Solution |
| 440 | K-th Smallest in Lexicographical Order | Solution | |
| 441 | Arranging Coins | Easy | Solution |
| 442 | Find All Duplicates in an Array | Medium | Solution |
| 443 | String Compression | Medium | Solution |
| 445 | Add Two Numbers II | Medium | Solution |
| 446 | Arithmetic Slices II - Subsequence | Hard | Solution |
| 447 | Number of Boomerangs | Solution | |
| 448 | Find All Numbers Disappeared in an Array | Easy | Solution |
| 449 | Serialize and Deserialize BST | Solution | |
| 450 | Delete Node in a BST | Medium | Solution |
| 451 | Sort Characters By Frequency | Medium | Solution |
| 452 | Minimum Number of Arrows to Burst Balloons | Medium | Solution |
| 453 | Minimum Moves to Equal Array Elements | Solution | |
| 454 | 4Sum II | Medium | Solution |
| 455 | Assign Cookies | Solution | |
| 456 | 132 Pattern | Medium | Solution |
| 457 | Circular Array Loop | Medium | Solution |
| 459 | Repeated Substring Pattern | Easy | Solution |
| 460 | LFU Cache | Solution | |
| 461 | Hamming Distance | Easy | Solution |
| 462 | Minimum Moves to Equal Array Elements II | Medium | Solution |
| 463 | Island Perimeter | Easy | Solution |
| 464 | Can I Win | Solution | |
| 466 | Count The Repetitions | Hard | Solution |
| 467 | Unique Substrings in Wraparound String | Solution | |
| 468 | Validate IP Address | Medium | Solution |
| 470 | Implement Rand10() Using Rand7() | Medium | Solution |
| 471 | Encode String with Shortest Length | Hard | Solution |
| 472 | Concatenated Words | Hard | Solution |
| 473 | Matchsticks to Square | Medium | Solution |
| 474 | Ones and Zeroes | Medium | Solution |
| 475 | Heaters | Solution | |
| 476 | Number Complement | Easy | Solution |
| 477 | Total Hamming Distance | Solution | |
| 478 | Generate Random Point in a Circle | Medium | Solution |
| 479 | Largest Palindrome Product | Hard | Solution |
| 480 | Sliding Window Median | Solution | |
| 481 | Magical String | Solution | |
| 482 | License Key Formatting | Solution | |
| 483 | Smallest Good Base | Hard | Solution |
| 485 | Max Consecutive Ones | Easy | Solution |
| 486 | Predict the Winner | Medium | Solution |
| 487 | Max Consecutive Ones II | Medium | Solution |
| 488 | Zuma Game | Solution | |
| 489 | Robot Room Cleaner | Hard | Solution |
| 490 | The Maze | Medium | Solution |
| 491 | Increasing Subsequences | Medium | Solution |
| 492 | Construct the Rectangle | Solution | |
| 493 | Reverse Pairs | Hard | Solution |
| 494 | Target Sum | Medium | Solution |
| 495 | Teemo Attacking | Medium | Solution |
| 496 | Next Greater Element I | Easy | Solution |
| 497 | Random Point in Non-overlapping Rectangles | Medium | Solution |
| 498 | Diagonal Traverse | Solution | |
| 499 | The Maze III | Hard | Solution |
| 500 | Keyboard Row | Easy | Solution |
| 501 | Find Mode in Binary Search Tree | Easy | Solution |
| 502 | IPO | Hard | Solution |
| 503 | Next Greater Element II | Medium | Solution |
| 504 | Base 7 | Easy | Solution |
| 505 | The Maze II | Medium | Solution |
| 506 | Relative Ranks | Easy | Solution |
| 507 | Perfect Number | Easy | Solution |
| 508 | Most Frequent Subtree Sum | Medium | Solution |
| 509 | Fibonacci Number | Easy | Solution |
| 510 | Inorder Successor in BST II | Medium | Solution |
| 513 | Find Bottom Left Tree Value | Medium | Solution |
| 514 | Freedom Trail | Hard | Solution |
| 515 | Find Largest Value in Each Tree Row | Medium | Solution |
| 516 | Longest Palindromic Subsequence | Medium | Solution |
| 517 | Super Washing Machines | Hard | Solution |
| 518 | Coin Change 2 | Medium | Solution |
| 519 | Random Flip Matrix | Medium | Solution |
| 520 | Detect Capital | Easy | Solution |
| 521 | Longest Uncommon Subsequence I | Easy | Solution |
| 522 | Longest Uncommon Subsequence II | Medium | Solution |
| 523 | Continuous Subarray Sum | Medium | Solution |
| 524 | Longest Word in Dictionary through Deleting | Medium | Solution |
| 525 | Contiguous Array | Medium | Solution |
| 526 | Beautiful Arrangement | Medium | Solution |
| 528 | Random Pick with Weight | Medium | Solution |
| 529 | Minesweeper | Medium | Solution |
| 530 | Minimum Absolute Difference in BST | Easy | Solution |
| 532 | K-diff Pairs in an Array | Medium | Solution |
| 535 | Encode and Decode TinyURL | Medium | Solution |
| 536 | Construct Binary Tree from String | Solution | |
| 537 | Complex Number Multiplication | Medium | Solution |
| 538 | Convert BST to Greater Tree | Medium | Solution |
| 539 | Minimum Time Difference | Solution | |
| 540 | Single Element in a Sorted Array | Medium | Solution |
| 541 | Reverse String II | Solution | |
| 542 | 01 Matrix | Medium | Solution |
| 543 | Diameter of Binary Tree | Easy | Solution |
| 544 | Output Contest Matches | Medium | Solution |
| 545 | Boundary of Binary Tree | Medium | Solution |
| 546 | Remove Boxes | Hard | Solution |
| 547 | Friend Circles | Medium | Solution |
| 549 | Binary Tree Longest Consecutive Sequence II | Medium | Solution |
| 551 | Student Attendance Record I | Easy | Solution |
| 552 | Student Attendance Record II | Hard | Solution |
| 553 | Optimal Division | Medium | Solution |
| 554 | Brick Wall | Medium | Solution |
| 556 | Next Greater Element III | Medium | Solution |
| 557 | Reverse Words in a String III | Solution | |
| 558 | Quad Tree Intersection | Easy | Solution |
| 559 | Maximum Depth of N-ary Tree | Easy | Solution |
| 560 | Subarray Sum Equals K | Medium | Solution |
| 561 | Array Partition I | Solution | |
| 562 | Longest Line of Consecutive One in Matrix | Solution | |
| 563 | Binary Tree Tilt | Easy | Solution |
| 564 | Find the Closest Palindrome | Hard | Solution |
| 565 | Array Nesting | Medium | Solution |
| 566 | Reshape the Matrix | Easy | Solution |
| 567 | Permutation in String | Medium | Solution |
| 568 | Maximum Vacation Days | Hard | Solution |
| 570 | Managers with at Least 5 Direct Reports | Medium | Solution |
| 572 | Subtree of Another Tree | Easy | Solution |
| 573 | Squirrel Simulation | Medium | Solution |
| 575 | Distribute Candies | Easy | Solution |
| 576 | Out of Boundary Paths | Medium | Solution |
| 577 | Employee Bonus | Easy | Solution |
| 581 | Shortest Unsorted Continuous Subarray | Medium | Solution |
| 582 | Kill Process | Medium | Solution |
| 583 | Delete Operation for Two Strings | Medium | Solution |
| 584 | Find Customer Referee | Easy | Solution |
| 586 | Customer Placing the Largest Number of Orders | Easy | Solution |
| 588 | Design In-Memory File System | Hard | Solution |
| 589 | N-ary Tree Preorder Traversal | Easy | Solution |
| 590 | N-ary Tree Postorder Traversal | Easy | Solution |
| 591 | Tag Validator | Hard | Solution |
| 592 | Fraction Addition and Subtraction | Medium | Solution |
| 593 | Valid Square | Medium | Solution |
| 594 | Longest Harmonious Subsequence | Easy | Solution |
| 595 | Big Countries | Easy | Solution |
| 597 | Friend Requests I: Overall Acceptance Rate | Easy | Solution |
| 598 | Range Addition II | Easy | Solution |
| 599 | Minimum Index Sum of Two Lists | Easy | Solution |
| 600 | Non-negative Integers without Consecutive Ones | Hard | Solution |
| 603 | Consecutive Available Seats | Easy | Solution |
| 604 | Design Compressed String Iterator | Easy | Solution |
| 605 | Can Place Flowers | Easy | Solution |
| 606 | Construct String from Binary Tree | Easy | Solution |
| 607 | Sales Person | Easy | Solution |
| 609 | Find Duplicate File in System | Medium | Solution |
| 610 | Triangle Judgement | Easy | Solution |
| 611 | Valid Triangle Number | Medium | Solution |
| 613 | Shortest Distance in a Line | Easy | Solution |
| 616 | Add Bold Tag in String | Medium | Solution |
| 617 | Merge Two Binary Trees | Easy | Solution |
| 620 | Not Boring Movies | Easy | Solution |
| 621 | Task Scheduler | Medium | Solution |
| 622 | Design Circular Queue | Medium | Solution |
| 623 | Add One Row to Tree | Medium | Solution |
| 624 | Maximum Distance in Arrays | Medium | Solution |
| 627 | Swap Salary | Easy | Solution |
| 628 | Maximum Product of Three Numbers | Easy | Solution |
| 629 | K Inverse Pairs Array | Hard | Solution |
| 630 | Course Schedule III | Hard | Solution |
| 632 | Smallest Range Covering Elements from K Lists | Hard | Solution |
| 636 | Exclusive Time of Functions | Medium | Solution |
| 637 | Average of Levels in Binary Tree | Easy | Solution |
| 638 | Shopping Offers | Medium | Solution |
| 639 | Decode Ways II | Hard | Solution |
| 640 | Solve the Equation | Medium | Solution |
| 641 | Design Circular Deque | Medium | Solution |
| 643 | Maximum Average Subarray I | Easy | Solution |
| 645 | Set Mismatch | Easy | Solution |
| 646 | Maximum Length of Pair Chain | Medium | Solution |
| 647 | Palindromic Substrings | Medium | Solution |
| 648 | Replace Words | Medium | Solution |
| 649 | Dota2 Senate | Medium | Solution |
| 650 | 2 Keys Keyboard | Medium | Solution |
| 651 | 4 Keys Keyboard | Medium | Solution |
| 652 | Find Duplicate Subtrees | Medium | Solution |
| 653 | Two Sum IV - Input is a BST | Easy | Solution |
| 654 | Maximum Binary Tree | Medium | Solution |
| 655 | Print Binary Tree | Medium | Solution |
| 657 | Robot Return to Origin | Easy | Solution |
| 658 | Find K Closest Elements | Medium | Solution |
| 659 | Split Array into Consecutive Subsequences | Medium | Solution |
| 661 | Image Smoother | Easy | Solution |
| 662 | Maximum Width of Binary Tree | Medium | Solution |
| 663 | Equal Tree Partition | Medium | Solution |
| 664 | Strange Printer | Hard | Solution |
| 665 | Non-decreasing Array | Medium | Solution |
| 666 | Path Sum IV | Medium | Solution |
| 667 | Beautiful Arrangement II | Medium | Solution |
| 668 | Kth Smallest Number in Multiplication Table | Hard | Solution |
| 669 | Trim a Binary Search Tree | Medium | Solution |
| 670 | Maximum Swap | Medium | Solution |
| 671 | Second Minimum Node In a Binary Tree | Easy | Solution |
| 672 | Bulb Switcher II | Medium | Solution |
| 673 | Number of Longest Increasing Subsequence | Medium | Solution |
| 674 | Longest Continuous Increasing Subsequence | Easy | Solution |
| 675 | Cut Off Trees for Golf Event | Hard | Solution |
| 676 | Implement Magic Dictionary | Medium | Solution |
| 677 | Map Sum Pairs | Medium | Solution |
| 678 | Valid Parenthesis String | Medium | Solution |
| 679 | 24 Game | Hard | Solution |
| 680 | Valid Palindrome II | Easy | Solution |
| 682 | Baseball Game | Easy | Solution |
| 684 | Redundant Connection | Medium | Solution |
| 685 | Redundant Connection II | Hard | Solution |
| 686 | Repeated String Match | Medium | Solution |
| 687 | Longest Univalue Path | Medium | Solution |
| 688 | Knight Probability in Chessboard | Medium | Solution |
| 689 | Maximum Sum of 3 Non-Overlapping Subarrays | Hard | Solution |
| 690 | Employee Importance | Easy | Solution |
| 691 | Stickers to Spell Word | Hard | Solution |
| 692 | Top K Frequent Words | Medium | Solution |
| 693 | Binary Number with Alternating Bits | Easy | Solution |
| 694 | Number of Distinct Islands | Medium | Solution |
| 695 | Max Area of Island | Medium | Solution |
| 696 | Count Binary Substrings | Easy | Solution |
| 697 | Degree of an Array | Easy | Solution |
| 698 | Partition to K Equal Sum Subsets | Medium | Solution |
| 699 | Falling Squares | Hard | Solution |
| 700 | Search in a Binary Search Tree | Easy | Solution |
| 701 | Insert into a Binary Search Tree | Medium | Solution |
| 702 | Search in a Sorted Array of Unknown Size | Medium | Solution |
| 703 | Kth Largest Element in a Stream | Easy | Solution |
| 704 | Binary Search | Easy | Solution |
| 705 | Design HashSet | Easy | Solution |
| 706 | Design HashMap | Easy | Solution |
| 707 | Design Linked List | Easy | Solution |
| 708 | Insert into a Sorted Circular Linked List | Medium | Solution |
| 709 | To Lower Case | Easy | Solution |
| 710 | Random Pick with Blacklist | Hard | Solution |
| 712 | Minimum ASCII Delete Sum for Two Strings | Medium | Solution |
| 713 | Subarray Product Less Than K | Medium | Solution |
| 714 | Best Time to Buy and Sell Stock with Transaction Fee | Medium | Solution |
| 715 | Range Module | Hard | Solution |
| 716 | Max Stack | Easy | Solution |
| 717 | 1-bit and 2-bit Characters | Easy | Solution |
| 718 | Maximum Length of Repeated Subarray | Medium | Solution |
| 719 | Find K-th Smallest Pair Distance | Hard | Solution |
| 720 | Longest Word in Dictionary | Easy | Solution |
| 721 | Accounts Merge | Medium | Solution |
| 722 | Remove Comments | Medium | Solution |
| 723 | Candy Crush | Medium | Solution |
| 724 | Find Pivot Index | Easy | Solution |
| 725 | Split Linked List in Parts | Medium | Solution |
| 726 | Number of Atoms | Hard | Solution |
| 728 | Self Dividing Numbers | Easy | Solution |
| 729 | My Calendar I | Medium | Solution |
| 730 | Count Different Palindromic Subsequences | Hard | Solution |
| 731 | My Calendar II | Medium | Solution |
| 732 | My Calendar III | Hard | Solution |
| 733 | Flood Fill | Easy | Solution |
| 734 | Sentence Similarity | Easy | Solution |
| 735 | Asteroid Collision | Medium | Solution |
| 736 | Parse Lisp Expression | Hard | Solution |
| 738 | Monotone Increasing Digits | Medium | Solution |
| 739 | Daily Temperatures | Medium | Solution |
| 740 | Delete and Earn | Medium | Solution |
| 741 | Cherry Pickup | Hard | Solution |
| 743 | Network Delay Time | Medium | Solution |
| 744 | Find Smallest Letter Greater Than Target | Easy | Solution |
| 745 | Prefix and Suffix Search | Hard | Solution |
| 746 | Min Cost Climbing Stairs | Easy | Solution |
| 747 | Largest Number At Least Twice of Others | Easy | Solution |
| 748 | Shortest Completing Word | Easy | Solution |
| 749 | Contain Virus | Hard | Solution |
| 750 | Number Of Corner Rectangles | Medium | Solution |
| 751 | IP to CIDR | Hard | Solution |
| 752 | Open the Lock | Medium | Solution |
| 753 | Cracking the Safe | Hard | Solution |
| 754 | Reach a Number | Easy | Solution |
| 755 | Pour Water | Medium | Solution |
| 756 | Pyramid Transition Matrix | Medium | Solution |
| 757 | Set Intersection Size At Least Two | Hard | Solution |
| 758 | Bold Words in String | Medium | Solution |
| 759 | Employee Free Time | Hard | Solution |
| 760 | Find Anagram Mappings | Easy | Solution |
| 761 | Special Binary String | Hard | Solution |
| 762 | Prime Number of Set Bits in Binary Representation | Easy | Solution |
| 763 | Partition Labels | Medium | Solution |
| 764 | Largest Plus Sign | Medium | Solution |
| 765 | Couples Holding Hands | Hard | Solution |
| 766 | Toeplitz Matrix | Easy | Solution |
| 767 | Reorganize String | Medium | Solution |
| 768 | Max Chunks To Make Sorted II | Hard | Solution |
| 769 | Max Chunks To Make Sorted | Medium | Solution |
| 770 | Basic Calculator IV | Hard | Solution |
| 771 | Jewels and Stones | Easy | Solution |
| 772 | Basic Calculator III | Hard | Solution |
| 773 | Sliding Puzzle | Hard | Solution |
| 774 | Minimize Max Distance to Gas Station | Hard | Solution |
| 775 | Global and Local Inversions | Medium | Solution |
| 777 | Swap Adjacent in LR String | Medium | Solution |
| 778 | Swim in Rising Water | Hard | Solution |
| 779 | K-th Symbol in Grammar | Medium | Solution |
| 780 | Reaching Points | Hard | Solution |
| 781 | Rabbits in Forest | Medium | Solution |
| 783 | Minimum Distance Between BST Nodes | Medium | Solution |
| 784 | Letter Case Permutation | Easy | Solution |
| 785 | Is Graph Bipartite? | Medium | Solution |
| 786 | K-th Smallest Prime Fraction | Hard | Solution |
| 787 | Cheapest Flights Within K Stops | Medium | Solution |
| 788 | Rotated Digits | Easy | Solution |
| 789 | Escape The Ghosts | Medium | Solution |
| 790 | Domino and Tromino Tiling | Medium | Solution |
| 791 | Custom Sort String | Medium | Solution |
| 792 | Number of Matching Subsequences | Medium | Solution |
| 793 | Preimage Size of Factorial Zeroes Function | Hard | Solution |
| 794 | Valid Tic-Tac-Toe State | Medium | Solution |
| 795 | Number of Subarrays with Bounded Maximum | Medium | Solution |
| 796 | Rotate String | Easy | Solution |
| 797 | All Paths From Source to Target | Medium | Solution |
| 798 | Smallest Rotation with Highest Score | Hard | Solution |
| 799 | Champagne Tower | Medium | Solution |
| 800 | Similar RGB Color | Easy | Solution |
| 801 | Minimum Swaps To Make Sequences Increasing | Medium | Solution |
| 802 | Find Eventual Safe States | Medium | Solution |
| 804 | Unique Morse Code Words | Easy | Solution |
| 805 | Split Array With Same Average | Hard | Solution |
| 806 | Number of Lines To Write String | Easy | Solution |
| 807 | Max Increase to Keep City Skyline | Medium | Solution |
| 808 | Soup Servings | Medium | Solution |
| 809 | Expressive Words | Medium | Solution |
| 810 | Chalkboard XOR Game | Hard | Solution |
| 811 | Subdomain Visit Count | Easy | Solution |
| 812 | Largest Triangle Area | Easy | Solution |
| 813 | Largest Sum of Averages | Medium | Solution |
| 814 | Binary Tree Pruning | Medium | Solution |
| 815 | Bus Routes | Hard | Solution |
| 816 | Ambiguous Coordinates | Medium | Solution |
| 817 | Linked List Components | Medium | Solution |
| 818 | Race Car | Hard | Solution |
| 819 | Most Common Word | Easy | Solution |
| 820 | Short Encoding of Words | Medium | Solution |
| 821 | Shortest Distance to a Character | Easy | Solution |
| 822 | Card Flipping Game | Medium | Solution |
| 823 | Binary Trees With Factors | Medium | Solution |
| 824 | Goat Latin | Easy | Solution |
| 825 | Friends Of Appropriate Ages | Medium | Solution |
| 826 | Most Profit Assigning Work | Medium | Solution |
| 827 | Making A Large Island | Hard | Solution |
| 828 | Unique Letter String | Hard | Solution |
| 829 | Consecutive Numbers Sum | Hard | Solution |
| 830 | Positions of Large Groups | Easy | Solution |
| 831 | Masking Personal Information | Medium | Solution |
| 832 | Flipping an Image | Easy | Solution |
| 833 | Find And Replace in String | Medium | Solution |
| 834 | Sum of Distances in Tree | Hard | Solution |
| 835 | Image Overlap | Medium | Solution |
| 836 | Rectangle Overlap | Easy | Solution |
| 837 | New 21 Game | Medium | Solution |
| 838 | Push Dominoes | Medium | Solution |
| 839 | Similar String Groups | Hard | Solution |
| 840 | Magic Squares In Grid | Easy | Solution |
| 841 | Keys and Rooms | Medium | Solution |
| 842 | Split Array into Fibonacci Sequence | Medium | Solution |
| 843 | Guess the Word | Hard | Solution |
| 844 | Backspace String Compare | Easy | Solution |
| 845 | Longest Mountain in Array | Medium | Solution |
| 846 | Hand of Straights | Medium | Solution |
| 847 | Shortest Path Visiting All Nodes | Hard | Solution |
| 848 | Shifting Letters | Medium | Solution |
| 849 | Maximize Distance to Closest Person | Medium | Solution |
| 851 | Loud and Rich | Medium | Solution |
| 852 | Peak Index in a Mountain Array | Easy | Solution |
| 853 | Car Fleet | Medium | Solution |
| 854 | K-Similar Strings | Hard | Solution |
| 855 | Exam Room | Medium | Solution |
| 856 | Score of Parentheses | Medium | Solution |
| 857 | Minimum Cost to Hire K Workers | Hard | Solution |
| 858 | Mirror Reflection | Medium | Solution |
| 859 | Buddy Strings | Easy | Solution |
| 860 | Lemonade Change | Easy | Solution |
| 861 | Score After Flipping Matrix | Medium | Solution |
| 862 | Shortest Subarray with Sum at Least K | Hard | Solution |
| 863 | All Nodes Distance K in Binary Tree | Medium | Solution |
| 864 | Shortest Path to Get All Keys | Hard | Solution |
| 865 | Smallest Subtree with all the Deepest Nodes | Medium | Solution |
| 866 | Prime Palindrome | Medium | Solution |
| 867 | Transpose Matrix | Easy | Solution |
| 868 | Binary Gap | Easy | Solution |
| 869 | Reordered Power of 2 | Medium | Solution |
| 870 | Advantage Shuffle | Medium | Solution |
| 871 | Minimum Number of Refueling Stops | Hard | Solution |
| 872 | Leaf-Similar Trees | Easy | Solution |
| 873 | Length of Longest Fibonacci Subsequence | Medium | Solution |
| 874 | Walking Robot Simulation | Easy | Solution |
| 875 | Koko Eating Bananas | Medium | Solution |
| 876 | Middle of the Linked List | Easy | Solution |
| 877 | Stone Game | Medium | Solution |
| 878 | Nth Magical Number | Hard | Solution |
| 879 | Profitable Schemes | Hard | Solution |
| 880 | Decoded String at Index | Medium | Solution |
| 881 | Boats to Save People | Medium | Solution |
| 882 | Reachable Nodes In Subdivided Graph | Hard | Solution |
| 883 | Projection Area of 3D Shapes | Easy | Solution |
| 884 | Uncommon Words from Two Sentences | Easy | Solution |
| 885 | Spiral Matrix III | Medium | Solution |
| 886 | Possible Bipartition | Medium | Solution |
| 887 | Super Egg Drop | Hard | Solution |
| 888 | Fair Candy Swap | Easy | Solution |
| 889 | Construct Binary Tree from Preorder and Postorder Traversal | Medium | Solution |
| 890 | Find and Replace Pattern | Medium | Solution |
| 891 | Sum of Subsequence Widths | Hard | Solution |
| 892 | Surface Area of 3D Shapes | Easy | Solution |
| 893 | Groups of Special-Equivalent Strings | Easy | Solution |
| 894 | All Possible Full Binary Trees | Medium | Solution |
| 895 | Maximum Frequency Stack | Hard | Solution |
| 896 | Monotonic Array | Easy | Solution |
| 897 | Increasing Order Search Tree | Easy | Solution |
| 898 | Bitwise ORs of Subarrays | Medium | Solution |
| 899 | Orderly Queue | Hard | Solution |
| 900 | RLE Iterator | Medium | Solution |
| 901 | Online Stock Span | Medium | Solution |
| 902 | Numbers At Most N Given Digit Set | Hard | Solution |
| 903 | Valid Permutations for DI Sequence | Hard | Solution |
| 904 | Fruit Into Baskets | Medium | Solution |
| 905 | Sort Array By Parity | Easy | Solution |
| 906 | Super Palindromes | Hard | Solution |
| 907 | Sum of Subarray Minimums | Medium | Solution |
| 908 | Smallest Range I | Easy | Solution |
| 909 | Snakes and Ladders | Medium | Solution |
| 911 | Online Election | Medium | Solution |
| 912 | Sort an Array | Medium | Solution |
| 913 | Cat and Mouse | Hard | Solution |
| 914 | X of a Kind in a Deck of Cards | Easy | Solution |
| 915 | Partition Array into Disjoint Intervals | Medium | Solution |
| 916 | Word Subsets | Medium | Solution |
| 917 | Reverse Only Letters | Easy | Solution |
| 918 | Maximum Sum Circular Subarray | Medium | Solution |
| 919 | Complete Binary Tree Inserter | Medium | Solution |
| 920 | Number of Music Playlists | Hard | Solution |
| 921 | Minimum Add to Make Parentheses Valid | Medium | Solution |
| 922 | Sort Array By Parity II | Easy | Solution |
| 923 | 3Sum With Multiplicity | Medium | Solution |
| 924 | Minimize Malware Spread | Hard | Solution |
| 925 | Long Pressed Name | Easy | Solution |
| 926 | Flip String to Monotone Increasing | Medium | Solution |
| 927 | Three Equal Parts | Hard | Solution |
| 928 | Minimize Malware Spread II | Hard | Solution |
| 929 | Unique Email Addresses | Easy | Solution |
| 930 | Binary Subarrays With Sum | Medium | Solution |
| 931 | Minimum Falling Path Sum | Medium | Solution |
| 932 | Beautiful Array | Medium | Solution |
| 933 | Number of Recent Calls | Easy | Solution |
| 934 | Shortest Bridge | Medium | Solution |
| 935 | Knight Dialer | Medium | Solution |
| 936 | Stamping The Sequence | Hard | Solution |
| 937 | Reorder Log Files | Easy | Solution |
| 938 | Range Sum of BST | Easy | Solution |
| 939 | Minimum Area Rectangle | Medium | Solution |
| 940 | Distinct Subsequences II | Hard | Solution |
| 941 | Valid Mountain Array | Easy | Solution |
| 942 | DI String Match | Easy | Solution |
| 943 | Find the Shortest Superstring | Hard | Solution |
| 944 | Delete Columns to Make Sorted | Easy | Solution |
| 945 | Minimum Increment to Make Array Unique | Medium | Solution |
| 946 | Validate Stack Sequences | Medium | Solution |
| 947 | Most Stones Removed with Same Row or Column | Medium | Solution |
| 948 | Bag of Tokens | Medium | Solution |
| 949 | Largest Time for Given Digits | Easy | Solution |
| 950 | Reveal Cards In Increasing Order | Medium | Solution |
| 951 | Flip Equivalent Binary Trees | Medium | Solution |
| 952 | Largest Component Size by Common Factor | Hard | Solution |
| 953 | Verifying an Alien Dictionary | Easy | Solution |
| 954 | Array of Doubled Pairs | Medium | Solution |
| 955 | Delete Columns to Make Sorted II | Medium | Solution |
| 956 | Tallest Billboard | Hard | Solution |
| 957 | Prison Cells After N Days | Medium | Solution |
| 958 | Check Completeness of a Binary Tree | Medium | Solution |
| 959 | Regions Cut By Slashes | Medium | Solution |
| 960 | Delete Columns to Make Sorted III | Hard | Solution |
| 961 | N-Repeated Element in Size 2N Array | Easy | Solution |
| 962 | Maximum Width Ramp | Medium | Solution |
| 963 | Minimum Area Rectangle II | Medium | Solution |
| 964 | Least Operators to Express Number | Hard | Solution |
| 967 | Numbers With Same Consecutive Differences | Medium | Solution |
| 968 | Binary Tree Cameras | Hard | Solution |
| 969 | Pancake Sorting | Medium | Solution |
| 970 | Powerful Integers | Easy | Solution |
| 971 | Flip Binary Tree To Match Preorder Traversal | Medium | Solution |
| 972 | Equal Rational Numbers | Hard | Solution |
| 973 | K Closest Points to Origin | Medium | Solution |
| 974 | Subarray Sums Divisible by K | Medium | Solution |
| 975 | Odd Even Jump | Hard | Solution |
| 977 | Squares of a Sorted Array | Easy | Solution |
| 978 | Longest Turbulent Subarray | Medium | Solution |
| 979 | Distribute Coins in Binary Tree | Medium | Solution |
| 980 | Unique Paths III | Hard | Solution |
| 981 | Time Based Key-Value Store | Medium | Solution |
| 982 | Triples with Bitwise AND Equal To Zero | Hard | Solution |
| 983 | Minimum Cost For Tickets | Medium | Solution |
| 984 | String Without AAA or BBB | Medium | Solution |
| 985 | Sum of Even Numbers After Queries | Easy | Solution |
| 986 | Interval List Intersections | Medium | Solution |
| 987 | Vertical Order Traversal of a Binary Tree | Medium | Solution |
| 988 | Smallest String Starting From Leaf | Medium | Solution |
| 989 | Add to Array-Form of Integer | Easy | Solution |
| 990 | Satisfiability of Equality Equations | Medium | Solution |
| 991 | Broken Calculator | Medium | Solution |
| 992 | Subarrays with K Different Integers | Hard | Solution |
| 993 | Cousins in Binary Tree | Easy | Solution |
| 994 | Rotting Oranges | Medium | Solution |
| 995 | Minimum Number of K Consecutive Bit Flips | Hard | Solution |
| 996 | Number of Squareful Arrays | Hard | Solution |
| 997 | Find the Town Judge | Easy | Solution |
| 998 | Maximum Binary Tree II | Medium | Solution |
| 999 | Available Captures for Rook | Easy | Solution |
| 1000 | Minimum Cost to Merge Stones | Hard | Solution |
| 1001 | Grid Illumination | Hard | Solution |
| 1002 | Find Common Characters | Easy | Solution |
| 1003 | Check If Word Is Valid After Substitutions | Medium | Solution |
| 1004 | Max Consecutive Ones III | Medium | Solution |
| 1005 | Maximize Sum Of Array After K Negations | Easy | Solution |
| 1006 | Clumsy Factorial | Medium | Solution |
| 1008 | Construct Binary Search Tree from Preorder Traversal | Medium | Solution |
| 1009 | Complement of Base 10 Integer | Easy | Solution |
| 1010 | Pairs of Songs With Total Durations Divisible by 60 | Medium | Solution |
| 1011 | Capacity To Ship Packages Within D Days | Medium | Solution |
| 1012 | Complement of Base 10 Integer | Easy | Solution |
| 1012 | Numbers With Repeated Digits | Hard | Solution |
| 1013 | Partition Array Into Three Parts With Equal Sum | Easy | Solution |
| 1014 | Best Sightseeing Pair | Medium | Solution |
| 1015 | Smallest Integer Divisible by K | Medium | Solution |
| 1016 | Binary String With Substrings Representing 1 To N | Medium | Solution |
| 1017 | Convert to Base -2 | Medium | Solution |
| 1018 | Binary Prefix Divisible By 5 | Easy | Solution |
| 1019 | Next Greater Node In Linked List | Medium | Solution |
| 1020 | Number of Enclaves | Medium | Solution |
| 1021 | Remove Outermost Parentheses | Easy | Solution |
| 1022 | Sum of Root To Leaf Binary Numbers | Easy | Solution |
| 1023 | Camelcase Matching | Medium | Solution |
| 1025 | Divisor Game | Easy | Solution |
| 1026 | Maximum Difference Between Node and Ancestor | Medium | Solution |
| 1027 | Longest Arithmetic Sequence | Medium | Solution |
| 1028 | Recover a Tree From Preorder Traversal | Hard | Solution |
| 1029 | Two City Scheduling | Medium | Solution |
| 1030 | Matrix Cells in Distance Order | Easy | Solution |
| 1031 | Maximum Sum of Two Non-Overlapping Subarrays | Medium | Solution |
| 1032 | Stream of Characters | Hard | Solution |
| 1033 | Moving Stones Until Consecutive | Easy | Solution |
| 1034 | Coloring A Border | Medium | Solution |
| 1035 | Uncrossed Lines | Medium | Solution |
| 1036 | Escape a Large Maze | Hard | Solution |
| 1037 | Valid Boomerang | Easy | Solution |
| 1038 | Binary Search Tree to Greater Sum Tree | Medium | Solution |
| 1039 | Minimum Score Triangulation of Polygon | Medium | Solution |
| 1040 | Moving Stones Until Consecutive II | Medium | Solution |
| 1041 | Robot Bounded In Circle | Medium | Solution |
| 1042 | Flower Planting With No Adjacent | Easy | Solution |
| 1043 | Partition Array for Maximum Sum | Medium | Solution |
| 1044 | Longest Duplicate Substring | Hard | Solution |
| 1046 | Last Stone Weight | Easy | Solution |
| 1047 | Remove All Adjacent Duplicates In String | Easy | Solution |
| 1048 | Longest String Chain | Medium | Solution |
| 1049 | Last Stone Weight II | Medium | Solution |
| 1051 | Height Checker | Easy | Solution |
| 1052 | Grumpy Bookstore Owner | Medium | Solution |
| 1053 | Previous Permutation With One Swap | Medium | Solution |
| 1054 | Distant Barcodes | Medium | Solution |
| 1055 | Shortest Way to Form String | Medium | Solution |
| 1056 | Confusing Number | Easy | Solution |
| 1057 | Campus Bikes | Medium | Solution |
| 1059 | All Paths from Source Lead to Destination | Medium | Solution |
| 1062 | Longest Repeating Substring | Medium | Solution |
| 1064 | Fixed Point | Easy | Solution |
| 1065 | Index Pairs of a String | Easy | Solution |
| 1071 | Greatest Common Divisor of Strings | Easy | Solution |
| 1072 | Flip Columns For Maximum Number of Equal Rows | Medium | Solution |
| 1073 | Adding Two Negabinary Numbers | Medium | Solution |
| 1074 | Number of Submatrices That Sum to Target | Hard | Solution |
| 1078 | Occurrences After Bigram | Easy | Solution |
| 1079 | Letter Tile Possibilities | Medium | Solution |
| 1080 | Insufficient Nodes in Root to Leaf Paths | Medium | Solution |
| 1081 | Smallest Subsequence of Distinct Characters | Medium | Solution |
| 1085 | Sum of Digits in the Minimum Number | Easy | Solution |
| 1086 | High Five | Easy | Solution |
| 1087 | Brace Expansion | Medium | Solution |
| 1089 | Duplicate Zeros | Easy | Solution |
| 1090 | Largest Values From Labels | Medium | Solution |
| 1091 | Shortest Path in Binary Matrix | Medium | Solution |
| 1092 | Shortest Common Supersequence | Hard | Solution |
| 1093 | Statistics from a Large Sample | Medium | Solution |
| 1094 | Car Pooling | Medium | Solution |
| 1095 | Find in Mountain Array | Hard | Solution |
| 1096 | Brace Expansion II | Hard | Solution |
| 1099 | Two Sum Less Than K | Easy | Solution |
| 1100 | Find K-Length Substrings With No Repeated Characters | Medium | Solution |
| 1101 | The Earliest Moment When Everyone Become Friends | Medium | Solution |
| 1102 | Path With Maximum Minimum Value | Medium | Solution |
| 1103 | Distribute Candies to People | Easy | Solution |
| 1104 | Path In Zigzag Labelled Binary Tree | Medium | Solution |
| 1105 | Filling Bookcase Shelves | Medium | Solution |
| 1106 | Parsing A Boolean Expression | Hard | Solution |
| 1108 | Defanging an IP Address | Easy | Solution |
| 1109 | Corporate Flight Bookings | Medium | Solution |
| 1110 | Delete Nodes And Return Forest | Medium | Solution |
| 1111 | Maximum Nesting Depth of Two Valid Parentheses Strings | Medium | Solution |
| 1118 | Number of Days in a Month | Easy | Solution |
| 1119 | Remove Vowels from a String | Easy | Solution |
| 1120 | Maximum Average Subtree | Medium | Solution |
| 1122 | Relative Sort Array | Easy | Solution |
| 1123 | Lowest Common Ancestor of Deepest Leaves | Medium | Solution |
| 1124 | Longest Well-Performing Interval | Medium | Solution |
| 1125 | Smallest Sufficient Team | Hard | Solution |
| 1128 | Number of Equivalent Domino Pairs | Easy | Solution |
| 1129 | Shortest Path with Alternating Colors | Medium | Solution |
| 1130 | Minimum Cost Tree From Leaf Values | Medium | Solution |
| 1131 | Maximum of Absolute Value Expression | Medium | Solution |
| 1133 | Largest Unique Number | Easy | Solution |
| 1134 | Armstrong Number | Easy | Solution |
| 1135 | Connecting Cities With Minimum Cost | Medium | Solution |
| 1136 | Parallel Courses | Medium | Solution |
| 1137 | N-th Tribonacci Number | Easy | Solution |
| 1138 | Alphabet Board Path | Medium | Solution |
| 1139 | Largest 1-Bordered Square | Medium | Solution |
| 1140 | Stone Game II | Medium | Solution |
| 1143 | Longest Common Subsequence | Medium | Solution |
| 1144 | Decrease Elements To Make Array Zigzag | Medium | Solution |
| 1145 | Binary Tree Coloring Game | Medium | Solution |
| 1146 | Snapshot Array | Medium | Solution |
| 1147 | Longest Chunked Palindrome Decomposition | Hard | Solution |
| 1150 | Check If a Number Is Majority Element in a Sorted Array | Easy | Solution |
| 1154 | Day of the Year | Easy | Solution |
| 1155 | Number of Dice Rolls With Target Sum | Medium | Solution |
| 1156 | Swap For Longest Repeated Character Substring | Medium | Solution |
| 1160 | Find Words That Can Be Formed by Characters | Easy | Solution |
| 1161 | Maximum Level Sum of a Binary Tree | Medium | Solution |
| 1162 | As Far from Land as Possible | Medium | Solution |
| 1163 | Last Substring in Lexicographical Order | Hard | Solution |
| 1165 | Single-Row Keyboard | Easy | Solution |
| 1166 | Design File System | Medium | Solution |
| 1167 | Minimum Cost to Connect Sticks | Medium | Solution |
| 1168 | Optimize Water Distribution in a Village | Hard | Solution |
| 1169 | Invalid Transactions | Medium | Solution |
| 1170 | Compare Strings by Frequency of the Smallest Character | Easy | Solution |
| 1171 | Remove Zero Sum Consecutive Nodes from Linked List | Medium | Solution |
| 1172 | Dinner Plate Stacks | Hard | Solution |
| 1175 | Prime Arrangements | Easy | Solution |
| 1176 | Diet Plan Performance | Easy | Solution |
| 1177 | Can Make Palindrome from Substring | Medium | Solution |
| 1178 | Number of Valid Words for Each Puzzle | Hard | Solution |
| 1180 | Count Substrings with Only One Distinct Letter | Easy | Solution |
| 1182 | Shortest Distance to Target Color | Medium | Solution |
| 1184 | Distance Between Bus Stops | Easy | Solution |
| 1185 | Day of the Week | Easy | Solution |
| 1186 | Maximum Subarray Sum with One Deletion | Medium | Solution |
| 1187 | Make Array Strictly Increasing | Hard | Solution |
| 1189 | Maximum Number of Balloons | Easy | Solution |
| 1190 | Reverse Substrings Between Each Pair of Parentheses | Medium | Solution |
| 1191 | K-Concatenation Maximum Sum | Medium | Solution |
| 1192 | Critical Connections in a Network | Hard | Solution |
| 1196 | How Many Apples Can You Put into the Basket | Easy | Solution |
| 1197 | Minimum Knight Moves | Medium | Solution |
| 1198 | Find Smallest Common Element in All Rows | Medium | Solution |
| 1200 | Minimum Absolute Difference | Easy | Solution |
| 1201 | Ugly Number III | Medium | Solution |
| 1202 | Smallest String With Swaps | Medium | Solution |
| 1203 | Sort Items by Groups Respecting Dependencies | Hard | Solution |
| 1206 | Design Skiplist | Hard | Solution |
| 1207 | Unique Number of Occurrences | Easy | Solution |
| 1208 | Get Equal Substrings Within Budget | Medium | Solution |
| 1209 | Remove All Adjacent Duplicates in String II | Medium | Solution |
| 1210 | Minimum Moves to Reach Target with Rotations | Hard | Solution |
| 1213 | Intersection of Three Sorted Arrays | Easy | Solution |
| 1214 | Two Sum BSTs | Medium | Solution |
| 1216 | Valid Palindrome III | Hard | Solution |
| 1217 | Minimum Cost to Move Chips to The Same Position | Easy | Solution |
| 1218 | Longest Arithmetic Subsequence of Given Difference | Medium | Solution |
| 1219 | Path with Maximum Gold | Medium | Solution |
| 1220 | Count Vowels Permutation | Hard | Solution |
| 1221 | Split a String in Balanced Strings | Easy | Solution |
| 1222 | Queens That Can Attack the King | Medium | Solution |
| 1223 | Dice Roll Simulation | Medium | Solution |
| 1224 | Maximum Equal Frequency | Hard | Solution |
| 1226 | The Dining Philosophers | Medium | Solution |
| 1227 | Airplane Seat Assignment Probability | Medium | Solution |
| 1228 | Missing Number In Arithmetic Progression | Easy | Solution |
| 1230 | Toss Strange Coins | Medium | Solution |
| 1231 | Divide Chocolate | Hard | Solution |
| 1232 | Check If It Is a Straight Line | Easy | Solution |
| 1233 | Remove Sub-Folders from the Filesystem | Medium | Solution |
| 1234 | Replace the Substring for Balanced String | Medium | Solution |
| 1235 | Maximum Profit in Job Scheduling | Hard | Solution |
| 1237 | Find Positive Integer Solution for a Given Equation | Easy | Solution |
| 1238 | Circular Permutation in Binary Representation | Medium | Solution |
| 1239 | Maximum Length of a Concatenated String with Unique Characters | Medium | Solution |
| 1240 | Tiling a Rectangle with the Fewest Squares | Hard | Solution |
| 1243 | Array Transformation | Easy | Solution |
| 1244 | Design A Leaderboard | Medium | Solution |
| 1245 | Tree Diameter | Medium | Solution |
| 1247 | Minimum Swaps to Make Strings Equal | Medium | Solution |
| 1248 | Count Number of Nice Subarrays | Medium | Solution |
| 1249 | Minimum Remove to Make Valid Parentheses | Medium | Solution |
| 1250 | Check If It Is a Good Array | Hard | Solution |
| 1252 | Cells with Odd Values in a Matrix | Easy | Solution |
| 1253 | Reconstruct a 2-Row Binary Matrix | Medium | Solution |
| 1254 | Number of Closed Islands | Medium | Solution |
| 1255 | Maximum Score Words Formed by Letters | Hard | Solution |
| 1256 | Encode Number | Medium | Solution |
| 1258 | Synonymous Sentences | Medium | Solution |
| 1260 | Shift 2D Grid | Easy | Solution |
| 1261 | Find Elements in a Contaminated Binary Tree | Medium | Solution |
| 1262 | Greatest Sum Divisible by Three | Medium | Solution |
| 1263 | Minimum Moves to Move a Box to Their Target Location | Hard | Solution |
| 1265 | Print Immutable Linked List in Reverse | Medium | Solution |
| 1266 | Minimum Time Visiting All Points | Easy | Solution |
| 1267 | Count Servers that Communicate | Medium | Solution |
| 1268 | Search Suggestions System | Medium | Solution |
| 1269 | Number of Ways to Stay in the Same Place After Some Steps | Hard | Solution |
| 1271 | Hexspeak | Easy | Solution |
| 1273 | Delete Tree Nodes | Medium | Solution |
| 1274 | Number of Ships in a Rectangle | Hard | Solution |
| 1275 | Find Winner on a Tic Tac Toe Game | Easy | Solution |
| 1276 | Number of Burgers with No Waste of Ingredients | Medium | Solution |
| 1277 | Count Square Submatrices with All Ones | Medium | Solution |
| 1278 | Palindrome Partitioning III | Hard | Solution |
| 1281 | Subtract the Product and Sum of Digits of an Integer | Easy | Solution |
| 1282 | Group the People Given the Group Size They Belong To | Medium | Solution |
| 1283 | Find the Smallest Divisor Given a Threshold | Medium | Solution |
| 1284 | Minimum Number of Flips to Convert Binary Matrix to Zero Matrix | Hard | Solution |
| 1286 | Iterator for Combination | Medium | Solution |
| 1287 | Element Appearing More Than 25% In Sorted Array | Easy | Solution |
| 1288 | Remove Covered Intervals | Medium | Solution |
| 1289 | Minimum Falling Path Sum II | Hard | Solution |
| 1290 | Convert Binary Number in a Linked List to Integer | Easy | Solution |
| 1291 | Sequential Digits | Medium | Solution |
| 1292 | Maximum Side Length of a Square with Sum Less than or Equal to Threshold | Medium | Solution |
| 1293 | Shortest Path in a Grid with Obstacles Elimination | Hard | Solution |
| 1295 | Find Numbers with Even Number of Digits | Easy | Solution |
| 1296 | Divide Array in Sets of K Consecutive Numbers | Medium | Solution |
| 1297 | Maximum Number of Occurrences of a Substring | Medium | Solution |
| 1298 | Maximum Candies You Can Get from Boxes | Hard | Solution |
| 1299 | Replace Elements with Greatest Element on Right Side | Easy | Solution |
| 1300 | Sum of Mutated Array Closest to Target | Medium | Solution |
| 1301 | Number of Paths with Max Score | Hard | Solution |
| 1302 | Deepest Leaves Sum | Medium | Solution |
| 1304 | Find N Unique Integers Sum up to Zero | Easy | Solution |
| 1305 | All Elements in Two Binary Search Trees | Medium | Solution |
| 1306 | Jump Game III | Medium | Solution |
| 1307 | Verbal Arithmetic Puzzle | Hard | Solution |
| 1309 | Decrypt String from Alphabet to Integer Mapping | Easy | Solution |
| 1310 | XOR Queries of a Subarray | Medium | Solution |
| 1311 | Get Watched Videos by Your Friends | Medium | Solution |
| 1312 | Minimum Insertion Steps to Make a String Palindrome | Hard | Solution |
| 1313 | Decompress Run-Length Encoded List | Easy | Solution |
| 1314 | Matrix Block Sum | Medium | Solution |
| 1315 | Sum of Nodes with Even-Valued Grandparent | Medium | Solution |
| 1316 | Distinct Echo Substrings | Hard | Solution |
| 1317 | Convert Integer to the Sum of Two No-Zero Integers | Easy | Solution |
| 1318 | Minimum Flips to Make a OR b Equal to c | Medium | Solution |
| 1319 | Number of Operations to Make Network Connected | Medium | Solution |
| 1320 | Minimum Distance to Type a Word Using Two Fingers | Hard | Solution |
| 1323 | Maximum 69 Number | Easy | Solution |
| 1324 | Print Words Vertically | Medium | Solution |
| 1325 | Delete Leaves With a Given Value | Medium | Solution |
| 1326 | Minimum Number of Taps to Open to Water a Garden | Hard | Solution |
| 1328 | Break a Palindrome | Medium | Solution |
| 1329 | Sort the Matrix Diagonally | Medium | Solution |
| 1330 | Reverse Subarray To Maximize Array Value | Hard | Solution |
| 1331 | Rank Transform of an Array | Easy | Solution |
| 1332 | Remove Palindromic Subsequences | Easy | Solution |
| 1333 | Filter Restaurants by Vegan-Friendly, Price and Distance | Medium | Solution |
| 1334 | Find the City With the Smallest Number of Neighbors at a Threshold Distance | Medium | Solution |
| 1335 | Minimum Difficulty of a Job Schedule | Hard | Solution |
| 1337 | The K Weakest Rows in a Matrix | Easy | Solution |
| 1338 | Reduce Array Size to The Half | Medium | Solution |
| 1339 | Maximum Product of Splitted Binary Tree | Medium | Solution |
| 1340 | Jump Game V | Hard | Solution |
| 1341 | The K Weakest Rows in a Matrix | Easy | Solution |
| 1342 | Number of Steps to Reduce a Number to Zero | Easy | Solution |
| 1343 | Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold | Medium | Solution |
| 1344 | Angle Between Hands of a Clock | Medium | Solution |
| 1345 | Jump Game IV | Hard | Solution |
| 1346 | Check If N and Its Double Exist | Easy | Solution |
| 1347 | Minimum Number of Steps to Make Two Strings Anagram | Medium | Solution |
| 1348 | Tweet Counts Per Frequency | Medium | Solution |
| 1349 | Maximum Students Taking Exam | Hard | Solution |
| 1351 | Count Negative Numbers in a Sorted Matrix | Easy | Solution |
| 1352 | Product of the Last K Numbers | Medium | Solution |
| 1353 | Maximum Number of Events That Can Be Attended | Medium | Solution |
| 1354 | Construct Target Array With Multiple Sums | Hard | Solution |
| 1356 | Sort Integers by The Number of 1 Bits | Easy | Solution |
| 1357 | Apply Discount Every n Orders | Medium | Solution |
| 1358 | Number of Substrings Containing All Three Characters | Medium | Solution |
| 1359 | Count All Valid Pickup and Delivery Options | Hard | Solution |
| 1360 | Number of Days Between Two Dates | Easy | Solution |
| 1361 | Validate Binary Tree Nodes | Medium | Solution |
| 1363 | Largest Multiple of Three | Hard | Solution |
| 1367 | Linked List in Binary Tree | Medium | Solution |
| 1368 | Minimum Cost to Make at Least One Valid Path in a Grid | Hard | Solution |
| 1370 | Increasing Decreasing String | Easy | Solution |
| 1371 | Find the Longest Substring Containing Vowels in Even Counts | Medium | Solution |
| 1372 | Longest ZigZag Path in a Binary Tree | Medium | Solution |
| 1373 | Maximum Sum BST in Binary Tree | Hard | Solution |
| 1374 | Generate a String With Characters That Have Odd Counts | Easy | Solution |
| 1375 | Bulb Switcher III | Medium | Solution |
| 1376 | Time Needed to Inform All Employees | Medium | Solution |
| 1377 | Frog Position After T Seconds | Hard | Solution |
| 1379 | Find a Corresponding Node of a Binary Tree in a Clone of That Tree | Medium | Solution |
| 1380 | Lucky Numbers in a Matrix | Easy | Solution |
| 1381 | Design a Stack With Increment Operation | Medium | Solution |
| 1382 | Balance a Binary Search Tree | Medium | Solution |
| 1383 | Maximum Performance of a Team | Hard | Solution |
| 1385 | Find the Distance Value Between Two Arrays | Easy | Solution |
| 1386 | Cinema Seat Allocation | Medium | Solution |
| 1387 | Sort Integers by The Power Value | Medium | Solution |
| 1388 | Pizza With 3n Slices | Hard | Solution |
| 1389 | Create Target Array in the Given Order | Easy | Solution |
| 1390 | Four Divisors | Medium | Solution |
| 1391 | Check if There is a Valid Path in a Grid | Medium | Solution |
| 1392 | Longest Happy Prefix | Hard | Solution |
| 1396 | Design Underground System | Medium | Solution |
| 1397 | Find All Good Strings | Hard | Solution |
| 1399 | Count Largest Group | Easy | Solution |
| 1400 | Construct K Palindrome Strings | Medium | Solution |
| 1401 | Circle and Rectangle Overlapping | Medium | Solution |
| 1402 | Reducing Dishes | Hard | Solution |
| 1403 | Minimum Subsequence in Non-Increasing Order | Easy | Solution |
| 1404 | Number of Steps to Reduce a Number in Binary Representation to One | Medium | Solution |
| 1405 | Longest Happy String | Medium | Solution |
| 1406 | Stone Game III | Hard | Solution |
| 1408 | String Matching in an Array | Easy | Solution |
| 1409 | Queries on a Permutation With Key | Medium | Solution |
| 1410 | HTML Entity Parser | Medium | Solution |
| 1411 | Number of Ways to Paint N × 3 Grid | Hard | Solution |
| 1413 | Minimum Value to Get Positive Step by Step Sum | Easy | Solution |
| 1414 | Find the Minimum Number of Fibonacci Numbers Whose Sum Is K | Medium | Solution |
| 1415 | The k-th Lexicographical String of All Happy Strings of Length n | Medium | Solution |
| 1416 | Restore The Array | Hard | Solution |
| 1419 | Minimum Number of Frogs Croaking | Medium | Solution |
| 1420 | Build Array Where You Can Find The Maximum Exactly K Comparisons | Hard | Solution |
| 1422 | Maximum Score After Splitting a String | Easy | Solution |
| 1423 | Maximum Points You Can Obtain from Cards | Medium | Solution |
| 1424 | Diagonal Traverse II | Medium | Solution |
| 1425 | Constrained Subsequence Sum | Hard | Solution |
| 1428 | Leftmost Column with at Least a One | Medium | Solution |
| 1429 | First Unique Number | Medium | Solution |
| 1430 | Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree | Medium | Solution |
| 1434 | Number of Ways to Wear Different Hats to Each Other | Hard | Solution |
| 1436 | Destination City | Easy | Solution |
| 1437 | Check If All 1's Are at Least Length K Places Away | Medium | Solution |
| 1438 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | Medium | Solution |
| 1439 | Find the Kth Smallest Sum of a Matrix With Sorted Rows | Hard | Solution |
| 1441 | Build an Array With Stack Operations | Solution | |
| 1442 | Count Triplets That Can Form Two Arrays of Equal XOR | Medium | Solution |
| 1443 | Minimum Time to Collect All Apples in a Tree | Medium | Solution |
| 1444 | Number of Ways of Cutting a Pizza | Hard | Solution |
| 1446 | Consecutive Characters | Easy | Solution |
| 1447 | Simplified Fractions | Medium | Solution |
| 1448 | Count Good Nodes in Binary Tree | Medium | Solution |
| 1449 | Form Largest Integer With Digits That Add up to Target | Hard | Solution |
| 1452 | People Whose List of Favorite Companies Is Not a Subset of Another List | Medium | Solution |
| 1453 | Maximum Number of Darts Inside of a Circular Dartboard | Hard | Solution |
| 1455 | Check If a Word Occurs As a Prefix of Any Word in a Sentence | Easy | Solution |
| 1456 | Maximum Number of Vowels in a Substring of Given Length | Medium | Solution |
| 1457 | Pseudo-Palindromic Paths in a Binary Tree | Medium | Solution |
| 1458 | Max Dot Product of Two Subsequences | Hard | Solution |
| 1460 | Make Two Arrays Equal by Reversing Sub-arrays | Easy | Solution |
| 1461 | Check If a String Contains All Binary Codes of Size K | Medium | Solution |
| 1462 | Course Schedule IV | Medium | Solution |
| 1463 | Cherry Pickup II | Hard | Solution |
| 1464 | Maximum Product of Two Elements in an Array | Easy | Solution |
| 1467 | Probability of a Two Boxes Having The Same Number of Distinct Balls | Hard | Solution |
| 1469 | Find All The Lonely Nodes | Easy | Solution |
| 1470 | Shuffle the Array | Easy | Solution |
| 1471 | The k Strongest Values in an Array | Medium | Solution |
| 1472 | Design Browser History | Medium | Solution |
| 1473 | Paint House III | Hard | Solution |
| 1474 | Delete N Nodes After M Nodes of a Linked List | Easy | Solution |
| 1475 | Final Prices With a Special Discount in a Shop | Easy | Solution |
| 1476 | Subrectangle Queries | Medium | Solution |
| 1477 | Find Two Non-overlapping Sub-arrays Each With Target Sum | Medium | Solution |
| 1478 | Allocate Mailboxes | Hard | Solution |
| 1480 | Running Sum of 1d Array | Easy | Solution |
| 1481 | Least Number of Unique Integers after K Removals | Medium | Solution |
| 1482 | Minimum Number of Days to Make m Bouquets | Medium | Solution |
| 1483 | Kth Ancestor of a Tree Node | Hard | Solution |
| 1485 | Clone Binary Tree With Random Pointer | Medium | Solution |
| 1486 | XOR Operation in an Array | Easy | Solution |
| 1487 | Making File Names Unique | Medium | Solution |
| 1488 | Avoid Flood in The City | Medium | Solution |
| 1489 | Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree | Hard | Solution |
| 1490 | Clone N-ary Tree | Medium | Solution |
| 1491 | Average Salary Excluding the Minimum and Maximum Salary | Easy | Solution |
| 1492 | The kth Factor of n | Medium | Solution |
| 1493 | Longest Subarray of 1's After Deleting One Element | Medium | Solution |
| 1494 | Parallel Courses II | Hard | Solution |
| 1496 | Path Crossing | Easy | Solution |
| 1497 | Check If Array Pairs Are Divisible by k | Medium | Solution |
| 1498 | Number of Subsequences That Satisfy the Given Sum Condition | Medium | Solution |
| 1499 | Max Value of Equation | Hard | Solution |
| 1502 | Can Make Arithmetic Progression From Sequence | Easy | Solution |
| 1503 | Last Moment Before All Ants Fall Out of a Plank | Medium | Solution |
| 1504 | Count Submatrices With All Ones | Medium | Solution |
| 1505 | Minimum Possible Integer After at Most K Adjacent Swaps On Digits | Hard | Solution |
| 1506 | Find Root of N-Ary Tree | Medium | Solution |
| 1507 | Reformat Date | Easy | Solution |
| 1508 | Range Sum of Sorted Subarray Sums | Medium | Solution |
| 1509 | Minimum Difference Between Largest and Smallest Value in Three Moves | Medium | Solution |
| 1510 | Stone Game IV | Hard | Solution |
| 1512 | Number of Good Pairs | Easy | Solution |
| 1513 | Number of Substrings With Only 1s | Medium | Solution |
| 1514 | Path with Maximum Probability | Medium | Solution |
| 1515 | Best Position for a Service Centre | Hard | Solution |
| 1518 | Water Bottles | Easy | Solution |
| 1519 | Number of Nodes in the Sub-Tree With the Same Label | Medium | Solution |
| 1520 | Maximum Number of Non-Overlapping Substrings | Medium | Solution |
| 1521 | Find a Value of a Mysterious Function Closest to Target | Hard | Solution |
| 1522 | Diameter of N-Ary Tree | Medium | Solution |
| 1523 | Count Odd Numbers in an Interval Range | Easy | Solution |
| 1524 | Number of Sub-arrays With Odd Sum | Medium | Solution |
| 1525 | Number of Good Ways to Split a String | Medium | Solution |
| 1526 | Minimum Number of Increments on Subarrays to Form a Target Array | Hard | Solution |
| 1531 | String Compression II | Hard | Solution |
| 1534 | Count Good Triplets | Easy | Solution |
| 1535 | Find the Winner of an Array Game | Medium | Solution |
| 1536 | Minimum Swaps to Arrange a Binary Grid | Medium | Solution |
| 1537 | Get the Maximum Score | Hard | Solution |
| 1539 | Kth Missing Positive Number | Easy | Solution |
| 1540 | Can Convert String in K Moves | Medium | Solution |
| 1541 | Minimum Insertions to Balance a Parentheses String | Medium | Solution |
| 1542 | Find Longest Awesome Substring | Hard | Solution |
| 1544 | Make The String Great | Easy | Solution |
| 1545 | Find Kth Bit in Nth Binary String | Medium | Solution |
| 1546 | Maximum Number of Non-Overlapping Subarrays With Sum Equals Target | Medium | Solution |
| 1547 | Minimum Cost to Cut a Stick | Hard | Solution |
| 1550 | Three Consecutive Odds | Easy | Solution |
| 1551 | Minimum Operations to Make Array Equal | Medium | Solution |
| 1552 | Magnetic Force Between Two Balls | Medium | Solution |
| 1553 | Minimum Number of Days to Eat N Oranges | Hard | Solution |
| 1554 | Strings Differ by One Character | Medium | Solution |
| 1556 | Thousand Separator | Easy | Solution |
| 1557 | Minimum Number of Vertices to Reach All Nodes | Medium | Solution |
| 1558 | Minimum Numbers of Function Calls to Make Target Array | Medium | Solution |
| 1559 | Detect Cycles in 2D Grid | Solution | |
| 1560 | Most Visited Sector in a Circular Track | Easy | Solution |
| 1561 | Maximum Number of Coins You Can Get | Medium | Solution |
| 1562 | Find Latest Group of Size M | Medium | Solution |
| 1563 | Stone Game V | Hard | Solution |
| 1564 | Put Boxes Into the Warehouse I | Medium | Solution |
| 1566 | Detect Pattern of Length M Repeated K or More Times | Easy | Solution |
| 1567 | Maximum Length of Subarray With Positive Product | Medium | Solution |
| 1568 | Minimum Number of Days to Disconnect Island | Medium | Solution |
| 1569 | Number of Ways to Reorder Array to Get Same BST | Hard | Solution |
| 1570 | Dot Product of Two Sparse Vectors | Medium | Solution |
| 1572 | Matrix Diagonal Sum | Easy | Solution |
| 1573 | Number of Ways to Split a String | Medium | Solution |
| 1574 | Shortest Subarray to be Removed to Make Array Sorted | Medium | Solution |
| 1575 | Count All Possible Routes | Hard | Solution |
| 1576 | Replace All ?'s to Avoid Consecutive Repeating Characters | Easy | Solution |
| 1577 | Number of Ways Where Square of Number Is Equal to Product of Two Numbers | Medium | Solution |
| 1578 | Minimum Deletion Cost to Avoid Repeating Letters | Medium | Solution |
| 1579 | Remove Max Number of Edges to Keep Graph Fully Traversable | Hard | Solution |
| 1580 | Put Boxes Into the Warehouse II | Medium | Solution |
| 1582 | Special Positions in a Binary Matrix | Easy | Solution |
| 1583 | Count Unhappy Friends | Medium | Solution |
| 1584 | Min Cost to Connect All Points | Medium | Solution |
| 1585 | Check If String Is Transformable With Substring Sort Operations | Hard | Solution |
| 1586 | Binary Search Tree Iterator II | Medium | Solution |
| 1588 | Sum of All Odd Length Subarrays | Easy | Solution |
| 1589 | Maximum Sum Obtained of Any Permutation | Medium | Solution |
| 1590 | Make Sum Divisible by P | Medium | Solution |
| 1591 | Strange Printer II | Hard | Solution |
| 1592 | Rearrange Spaces Between Words | Easy | Solution |
| 1593 | Split a String Into the Max Number of Unique Substrings | Medium | Solution |
| 1594 | Maximum Non Negative Product in a Matrix | Medium | Solution |
| 1595 | Minimum Cost to Connect Two Groups of Points | Hard | Solution |
| 1598 | Crawler Log Folder | Easy | Solution |
| 1599 | Maximum Profit of Operating a Centennial Wheel | Medium | Solution |
| 1600 | Throne Inheritance | Medium | Solution |
| 1601 | Maximum Number of Achievable Transfer Requests | Hard | Solution |
| 1602 | Find Nearest Right Node in Binary Tree | Medium | Solution |
| 1603 | Design Parking System | Easy | Solution |
| 1604 | Alert Using Same Key-Card Three or More Times in a One Hour Period | Medium | Solution |
| 1605 | Find Valid Matrix Given Row and Column Sums | Medium | Solution |
| 1606 | Find Servers That Handled Most Number of Requests | Hard | Solution |
| 1608 | Special Array With X Elements Greater Than or Equal X | Easy | Solution |
| 1609 | Even Odd Tree | Medium | Solution |
| 1610 | Maximum Number of Visible Points | Medium | Solution |
| 1611 | Minimum One Bit Operations to Make Integers Zero | Hard | Solution |
| 1614 | Maximum Nesting Depth of the Parentheses | Easy | Solution |
| 1615 | Maximal Network Rank | Medium | Solution |
| 1616 | Split Two Strings to Make Palindrome | Medium | Solution |
| 1617 | Count Subtrees With Max Distance Between Cities | Hard | Solution |
| 1619 | Mean of Array After Removing Some Elements | Easy | Solution |
| 1620 | Coordinate With Maximum Network Quality | Medium | Solution |
| 1621 | Number of Sets of K Non-Overlapping Line Segments | Medium | Solution |
| 1622 | Fancy Sequence | Hard | Solution |
| 1624 | Largest Substring Between Two Equal Characters | Easy | Solution |
| 1625 | Lexicographically Smallest String After Applying Operations | Medium | Solution |
| 1626 | Best Team With No Conflicts | Medium | Solution |
| 1627 | Graph Connectivity With Threshold | Hard | Solution |
| 1629 | Slowest Key | Easy | Solution |
| 1631 | Path With Minimum Effort | Medium | Solution |
| 1632 | Rank Transform of a Matrix | Hard | Solution |
| 1636 | Sort Array by Increasing Frequency | Easy | Solution |
| 1637 | Widest Vertical Area Between Two Points Containing No Points | Medium | Solution |
| 1638 | Count Substrings That Differ by One Character | Medium | Solution |
| 1639 | Number of Ways to Form a Target String Given a Dictionary | Hard | Solution |
| 1640 | Check Array Formation Through Concatenation | Easy | Solution |
| 1641 | Count Sorted Vowel Strings | Medium | Solution |
| 1642 | Furthest Building You Can Reach | Medium | Solution |
| 1643 | Kth Smallest Instructions | Hard | Solution |
| 1644 | Lowest Common Ancestor of a Binary Tree II | Medium | Solution |
| 1647 | Minimum Deletions to Make Character Frequencies Unique | Medium | Solution |
| 1648 | Sell Diminishing-Valued Colored Balls | Medium | Solution |
| 1649 | Create Sorted Array through Instructions | Hard | Solution |
| 1650 | Lowest Common Ancestor of a Binary Tree III | Medium | Solution |
| 1653 | Minimum Deletions to Make String Balanced | Medium | Solution |
| 1654 | Minimum Jumps to Reach Home | Medium | Solution |
| 1657 | Determine if Two Strings Are Close | Medium | Solution |
| 1658 | Minimum Operations to Reduce X to Zero | Medium | Solution |
| 1659 | Maximize Grid Happiness | Hard | Solution |
| 1660 | Correct a Binary Tree | Medium | Solution |
| 1662 | Check If Two String Arrays are Equivalent | Easy | Solution |
| 1663 | Smallest String With A Given Numeric Value | Medium | Solution |
| 1664 | Ways to Make a Fair Array | Medium | Solution |
| 1665 | Minimum Initial Energy to Finish Tasks | Hard | Solution |
| 1668 | Maximum Repeating Substring | Easy | Solution |
| 1669 | Merge In Between Linked Lists | Medium | Solution |
| 1670 | Design Front Middle Back Queue | Medium | Solution |
| 1671 | Minimum Number of Removals to Make Mountain Array | Hard | Solution |
| 1672 | Richest Customer Wealth | Easy | Solution |
| 1673 | Find the Most Competitive Subsequence | Medium | Solution |
| 1674 | Minimum Moves to Make Array Complementary | Medium | Solution |
| 1675 | Minimize Deviation in Array | Hard | Solution |
| 1676 | Lowest Common Ancestor of a Binary Tree IV | Medium | Solution |
| 1678 | Goal Parser Interpretation | Easy | Solution |
| 1679 | Max Number of K-Sum Pairs | Medium | Solution |
| 1680 | Concatenation of Consecutive Binary Numbers | Medium | Solution |
| 1681 | Minimum Incompatibility | Hard | Solution |
| 1685 | Sum of Absolute Differences in a Sorted Array | Medium | Solution |
| 1687 | Delivering Boxes from Storage to Ports | Hard | Solution |
| 1688 | Count of Matches in Tournament | Easy | Solution |
| 1689 | Partitioning Into Minimum Number Of Deci-Binary Numbers | Medium | Solution |
| 1690 | Stone Game VII | Medium | Solution |
| 1691 | Maximum Height by Stacking Cuboids | Hard | Solution |
| 1694 | Reformat Phone Number | Easy | Solution |
| 1695 | Maximum Erasure Value | Medium | Solution |
| 1696 | Jump Game VI | Medium | Solution |
| 1697 | Checking Existence of Edge Length Limited Paths | Hard | Solution |
| 1698 | Number of Distinct Substrings in a String | Medium | Solution |
| 1700 | Number of Students Unable to Eat Lunch | Easy | Solution |
| 1701 | Average Waiting Time | Medium | Solution |
| 1702 | Maximum Binary String After Change | Medium | Solution |
| 1704 | Determine if String Halves Are Alike | Easy | Solution |
| 1705 | Maximum Number of Eaten Apples | Medium | Solution |
| 1706 | Where Will the Ball Fall | Medium | Solution |
| 1707 | Maximum XOR With an Element From Array | Hard | Solution |
| 1708 | Largest Subarray Length K | Easy | Solution |
| 1710 | Maximum Units on a Truck | Easy | Solution |
| 1711 | Count Good Meals | Medium | Solution |
| 1712 | Ways to Split Array Into Three Subarrays | Medium | Solution |
| 1713 | Minimum Operations to Make a Subsequence | Hard | Solution |
| 1716 | Calculate Money in Leetcode Bank | Easy | Solution |
| 1717 | Maximum Score From Removing Substrings | Medium | Solution |
| 1718 | Construct the Lexicographically Largest Valid Sequence | Medium | Solution |
| 1719 | Number Of Ways To Reconstruct A Tree | Hard | Solution |
| 1720 | Decode XORed Array | Easy | Solution |
| 1721 | Swapping Nodes in a Linked List | Medium | Solution |
| 1722 | Minimize Hamming Distance After Swap Operations | Medium | Solution |
| 1723 | Find Minimum Time to Finish All Jobs | Hard | Solution |
| 1727 | Largest Submatrix With Rearrangements | Medium | Solution |
| 1730 | Shortest Path to Get Food | Medium | Solution |
| 1732 | Find the Highest Altitude | Easy | Solution |
| 1733 | Minimum Number of People to Teach | Medium | Solution |
| 1734 | Decode XORed Permutation | Medium | Solution |
| 1735 | Count Ways to Make Array With Product | Hard | Solution |
| 1736 | Latest Time by Replacing Hidden Digits | Easy | Solution |
| 1737 | Change Minimum Characters to Satisfy One of Three Conditions | Medium | Solution |
| 1738 | Find Kth Largest XOR Coordinate Value | Medium | Solution |
| 1739 | Building Boxes | Hard | Solution |
| 1740 | Find Distance in a Binary Tree | Medium | Solution |
| 1744 | Can You Eat Your Favorite Candy on Your Favorite Day? | Medium | Solution |
| 1745 | Palindrome Partitioning IV | Hard | Solution |
| 1748 | Sum of Unique Elements | Easy | Solution |
| 1749 | Maximum Absolute Sum of Any Subarray | Medium | Solution |
| 1750 | Minimum Length of String After Deleting Similar Ends | Medium | Solution |
| 1751 | Maximum Number of Events That Can Be Attended II | Hard | Solution |
| 1754 | Largest Merge Of Two Strings | Medium | Solution |
| 1755 | Closest Subsequence Sum | Hard | Solution |
| 1762 | Buildings With an Ocean View | Medium | Solution |
| 1763 | Longest Nice Substring | Easy | Solution |
| 1764 | Form Array by Concatenating Subarrays of Another Array | Medium | Solution |
| 1765 | Map of Highest Peak | Medium | Solution |
| 1766 | Tree of Coprimes | Hard | Solution |
| 1768 | Merge Strings Alternately | Easy | Solution |
| 1769 | Minimum Number of Operations to Move All Balls to Each Box | Medium | Solution |
| 1770 | Maximum Score from Performing Multiplication Operations | Medium | Solution |
| 1771 | Maximize Palindrome Length From Subsequences | Hard | Solution |
| 1772 | Sort Features by Popularity | Medium | Solution |
| 1773 | Count Items Matching a Rule | Easy | Solution |
| 1774 | Closest Dessert Cost | Medium | Solution |
| 1775 | Equal Sum Arrays With Minimum Number of Operations | Medium | Solution |
| 1779 | Find Nearest Point That Has the Same X or Y Coordinate | Easy | Solution |
| 1780 | Check if Number is a Sum of Powers of Three | Medium | Solution |
| 1781 | Sum of Beauty of All Substrings | Medium | Solution |
| 1784 | Check if Binary String Has at Most One Segment of Ones | Easy | Solution |
| 1785 | Minimum Elements to Add to Form a Given Sum | Medium | Solution |
| 1786 | Number of Restricted Paths From First to Last Node | Medium | Solution |
| 1787 | Make the XOR of All Segments Equal to Zero | Hard | Solution |
| 1790 | Check if One String Swap Can Make Strings Equal | Easy | Solution |
| 1791 | Find Center of Star Graph | Medium | Solution |
| 1792 | Maximum Average Pass Ratio | Medium | Solution |
| 1793 | Maximum Score of a Good Subarray | Hard | Solution |
| 1796 | Second Largest Digit in a String | Easy | Solution |
| 1797 | Design Authentication Manager | Medium | Solution |
| 1798 | Maximum Number of Consecutive Values You Can Make | Medium | Solution |
| 1799 | Maximize Score After N Operations | Hard | Solution |
| 1800 | Maximum Ascending Subarray Sum | Easy | Solution |
| 1801 | Number of Orders in the Backlog | Medium | Solution |
| 1802 | Maximum Value at a Given Index in a Bounded Array | Medium | Solution |
| 1803 | Count Pairs With XOR in a Range | Hard | Solution |
| 1804 | Implement Trie II (Prefix Tree) | Medium | Solution |
| 1806 | Minimum Number of Operations to Reinitialize a Permutation | Medium | Solution |
| 1807 | Evaluate the Bracket Pairs of a String | Medium | Solution |
| 1808 | Maximize Number of Nice Divisors | Hard | Solution |
| 1810 | Minimum Path Cost in a Hidden Grid | Medium | Solution |
| 1812 | Determine Color of a Chessboard Square | Easy | Solution |
| 1813 | Sentence Similarity III | Medium | Solution |
| 1814 | Count Nice Pairs in an Array | Medium | Solution |
| 1815 | Maximum Number of Groups Getting Fresh Donuts | Hard | Solution |
| 1816 | Truncate Sentence | Easy | Solution |
| 1817 | Finding the Users Active Minutes | Medium | Solution |
| 1818 | Minimum Absolute Sum Difference | Medium | Solution |
| 1819 | Number of Different Subsequences GCDs | Hard | Solution |
| 1820 | Maximum Number of Accepted Invitations | Medium | Solution |
| 1822 | Sign of the Product of an Array | Easy | Solution |
| 1823 | Find the Winner of the Circular Game | Medium | Solution |
| 1824 | Minimum Sideway Jumps | Medium | Solution |
| 1825 | Finding MK Average | Hard | Solution |
| 1826 | Faulty Sensor | Easy | Solution |
| 1827 | Minimum Operations to Make the Array Increasing | Easy | Solution |
| 1828 | Queries on Number of Points Inside a Circle | Medium | Solution |
| 1829 | Maximum XOR for Each Query | Medium | Solution |
| 1830 | Minimum Number of Operations to Make String Sorted | Hard | Solution |
| 1832 | Check if the Sentence Is Pangram | Easy | Solution |
| 1833 | Maximum Ice Cream Bars | Medium | Solution |
| 1834 | Single-Threaded CPU | Medium | Solution |
| 1835 | Find XOR Sum of All Pairs Bitwise AND | Hard | Solution |
| 1836 | Remove Duplicates From an Unsorted Linked List | Medium | Solution |
| 1837 | Sum of Digits in Base K | Easy | Solution |
| 1838 | Frequency of the Most Frequent Element | Medium | Solution |
| 1839 | Longest Substring Of All Vowels in Order | Medium | Solution |
| 1840 | Maximum Building Height | Hard | Solution |
| 1844 | Replace All Digits with Characters | Easy | Solution |
| 1845 | Seat Reservation Manager | Medium | Solution |
| 1846 | Maximum Element After Decreasing and Rearranging | Medium | Solution |
| 1847 | Closest Room | Hard | Solution |
| 1848 | Minimum Distance to the Target Element | Easy | Solution |
| 1849 | Splitting a String Into Descending Consecutive Values | Medium | Solution |
| 1850 | Minimum Adjacent Swaps to Reach the Kth Smallest Number | Medium | Solution |
| 1851 | Minimum Interval to Include Each Query | Hard | Solution |
| 1852 | Distinct Numbers in Each Subarray | Medium | Solution |
| 1854 | Maximum Population Year | Easy | Solution |
| 1855 | Maximum Distance Between a Pair of Values | Medium | Solution |
| 1856 | Maximum Subarray Min-Product | Medium | Solution |
| 1857 | Largest Color Value in a Directed Graph | Hard | Solution |
| 1858 | Longest Word With All Prefixes | Medium | Solution |
| 1859 | Sorting the Sentence | Easy | Solution |
| 1860 | Incremental Memory Leak | Medium | Solution |
| 1861 | Rotating the Box | Medium | Solution |
| 1862 | Sum of Floored Pairs | Hard | Solution |
| 1863 | Sum of All Subset XOR Totals | Easy | Solution |
| 1864 | Minimum Number of Swaps to Make the Binary String Alternating | Medium | Solution |
| 1865 | Finding Pairs With a Certain Sum | Medium | Solution |
| 1866 | Number of Ways to Rearrange Sticks With K Sticks Visible | Hard | Solution |
| 1869 | Longer Contiguous Segments of Ones than Zeros | Easy | Solution |
| 1870 | Minimum Speed to Arrive on Time | Medium | Solution |
| 1871 | Jump Game VII | Medium | Solution |
| 1872 | Stone Game VIII | Hard | Solution |
| 1874 | Minimize Product Sum of Two Arrays | Medium | Solution |
| 1876 | Substrings of Size Three with Distinct Characters | Easy | Solution |
| 1877 | Minimize Maximum Pair Sum in Array | Medium | Solution |
| 1878 | Get Biggest Three Rhombus Sums in a Grid | Medium | Solution |
| 1879 | Minimum XOR Sum of Two Arrays | Hard | Solution |
| 1880 | Check if Word Equals Summation of Two Words | Easy | Solution |
| 1881 | Maximum Value after Insertion | Medium | Solution |
| 1882 | Process Tasks Using Servers | Medium | Solution |
| 1883 | Minimum Skips to Arrive at Meeting On Time | Hard | Solution |
| 1884 | Egg Drop With 2 Eggs and N Floors | Medium | Solution |
| 1886 | Determine Whether Matrix Can Be Obtained By Rotation | Easy | Solution |
| 1887 | Reduction Operations to Make the Array Elements Equal | Medium | Solution |
| 1888 | Minimum Number of Flips to Make the Binary String Alternating | Medium | Solution |
| 1889 | Minimum Space Wasted From Packaging | Hard | Solution |
| 1893 | Check if All the Integers in a Range Are Covered | Easy | Solution |
| 1894 | Find the Student that Will Replace the Chalk | Medium | Solution |
| 1895 | Largest Magic Square | Medium | Solution |
| 1896 | Minimum Cost to Change the Final Value of Expression | Hard | Solution |
| 1897 | Redistribute Characters to Make All Strings Equal | Easy | Solution |
| 1898 | Maximum Number of Removable Characters | Medium | Solution |
| 1899 | Merge Triplets to Form Target Triplet | Medium | Solution |
| 1900 | The Earliest and Latest Rounds Where Players Compete | Hard | Solution |
| 1901 | Find a Peak Element II | Medium | Solution |
| 1902 | Depth of BST Given Insertion Order | Medium | Solution |
| 1903 | Largest Odd Number in String | Easy | Solution |
| 1904 | The Number of Full Rounds You Have Played | Medium | Solution |
| 1905 | Count Sub Islands | Medium | Solution |
| 1906 | Minimum Absolute Difference Queries | Medium | Solution |
| 1909 | Remove One Element to Make the Array Strictly Increasing | Easy | Solution |
| 1910 | Remove All Occurrences of a Substring | Medium | Solution |
| 1911 | Maximum Alternating Subsequence Sum | Medium | Solution |
| 1912 | Design Movie Rental System | Hard | Solution |
| 1913 | Maximum Product Difference Between Two Pairs | Easy | Solution |
| 1914 | Cyclically Rotating a Grid | Medium | Solution |
| 1915 | Number of Wonderful Substrings | Medium | Solution |
| 1920 | Build Array from Permutation | Easy | Solution |
| 1921 | Eliminate Maximum Number of Monsters | Medium | Solution |
| 1922 | Count Good Numbers | Medium | Solution |
| 1923 | Longest Common Subpath | Hard | Solution |
| 1925 | Count Square Sum Triples | Easy | Solution |
| 1926 | Nearest Exit from Entrance in Maze | Medium | Solution |
| 1927 | Sum Game | Medium | Solution |
| 1928 | Minimum Cost to Reach Destination in Time | Hard | Solution |
| 1929 | Concatenation of Array | Easy | Solution |
| 1930 | Unique Length-3 Palindromic Subsequences | Medium | Solution |
| 1931 | Painting a Grid With Three Different Colors | Hard | Solution |
| 1933 | Check if String Is Decomposable Into Value-Equal Substrings | Easy | Solution |
| 1935 | Maximum Number of Words You Can Type | Easy | Solution |
| 1936 | Add Minimum Number of Rungs | Medium | Solution |
| 1937 | Maximum Number of Points with Cost | Medium | Solution |
| 1938 | Maximum Genetic Difference Query | Hard | Solution |
| 1940 | Longest Common Subsequence Between Sorted Arrays | Medium | Solution |
| 1941 | Check if All Characters Have Equal Number of Occurrences | Easy | Solution |
| 1942 | The Number of the Smallest Unoccupied Chair | Medium | Solution |
| 1943 | Describe the Painting | Medium | Solution |
| 1944 | Number of Visible People in a Queue | Hard | Solution |
| 1945 | Sum of Digits of String After Convert | Easy | Solution |
| 1946 | Largest Number After Mutating Substring | Medium | Solution |
| 1947 | Maximum Compatibility Score Sum | Solution | |
| 1948 | Delete Duplicate Folders in System | Hard | Solution |
| 1952 | Three Divisors | Easy | Solution |
| 1953 | Maximum Number of Weeks for Which You Can Work | Medium | Solution |
| 1954 | Minimum Garden Perimeter to Collect Enough Apples | Medium | Solution |
| 1955 | Count Number of Special Subsequences | Hard | Solution |
| 1957 | Delete Characters to Make Fancy String | Easy | Solution |
| 1958 | Check if Move is Legal | Medium | Solution |
| 1959 | Minimum Total Space Wasted With K Resizing Operations | Medium | Solution |
| 1960 | Maximum Product of the Length of Two Palindromic Substrings | Hard | Solution |
| 1961 | Check If String Is a Prefix of Array | Easy | Solution |
| 1962 | Remove Stones to Minimize the Total | Medium | Solution |
| 1963 | Minimum Number of Swaps to Make the String Balanced | Medium | Solution |
| 1964 | Find the Longest Valid Obstacle Course at Each Position | Hard | Solution |
| 1967 | Number of Strings That Appear as Substrings in Word | Easy | Solution |
| 1968 | Array With Elements Not Equal to Average of Neighbors | Medium | Solution |
| 1969 | Minimum Non-Zero Product of the Array Elements | Medium | Solution |
| 1971 | Find if Path Exists in Graph | Easy | Solution |
| 1973 | Count Nodes Equal to Sum of Descendants | Medium | Solution |
| 1974 | Minimum Time to Type Word Using Special Typewriter | Easy | Solution |
| 1975 | Maximum Matrix Sum | Medium | Solution |
| 1976 | Number of Ways to Arrive at Destination | Medium | Solution |
| 1977 | Number of Ways to Separate Numbers | Hard | Solution |
| 1979 | Find Greatest Common Divisor of Array | Easy | Solution |
| 1980 | Find Unique Binary String | Medium | Solution |
| 1981 | Minimize the Difference Between Target and Chosen Elements | Medium | Solution |
| 1982 | Find Array Given Subset Sums | Hard | Solution |
| 1984 | Minimum Difference Between Highest and Lowest of K Scores | Easy | Solution |
| 1985 | Find the Kth Largest Integer in the Array | Medium | Solution |
| 1986 | Minimum Number of Work Sessions to Finish the Tasks | Medium | Solution |
| 1987 | Number of Unique Good Subsequences | Hard | Solution |
| 1991 | Find the Middle Index in Array | Easy | Solution |
| 1992 | Find All Groups of Farmland | Medium | Solution |
| 1993 | Operations on Tree | Medium | Solution |
| 1994 | The Number of Good Subsets | Hard | Solution |
| 1995 | Count Special Quadruplets | Easy | Solution |
| 1996 | The Number of Weak Characters in the Game | Medium | Solution |
| 1997 | First Day Where You Have Been in All the Rooms | Medium | Solution |
| 1998 | GCD Sort of an Array | Hard | Solution |
| 2000 | Reverse Prefix of Word | Easy | Solution |
| 2001 | Number of Pairs of Interchangeable Rectangles | Medium | Solution |
| 2002 | Maximum Product of the Length of Two Palindromic Subsequences | Medium | Solution |
| 2003 | Smallest Missing Genetic Value in Each Subtree | Hard | Solution |
| 2006 | Count Number of Pairs With Absolute Difference K | Easy | Solution |
| 2007 | Find Original Array From Doubled Array | Medium | Solution |
| 2008 | Maximum Earnings From Taxi | Medium | Solution |
| 2009 | Minimum Number of Operations to Make Array Continuous | Hard | Solution |
| 2011 | Final Value of Variable After Performing Operations | Easy | Solution |
| 2012 | Sum of Beauty in the Array | Medium | Solution |
| 2013 | Detect Squares | Medium | Solution |
| 2014 | Longest Subsequence Repeated k Times | Hard | Solution |
| 2016 | Maximum Difference Between Increasing Elements | Easy | Solution |
| 2017 | Grid Game | Medium | Solution |
| 2018 | Check if Word Can Be Placed In Crossword | Medium | Solution |
| 2019 | The Score of Students Solving Math Expression | Hard | Solution |
| 2021 | Brightest Position on Street | Medium | Solution |
| 2022 | Convert 1D Array Into 2D Array | Easy | Solution |
| 2023 | Number of Pairs of Strings With Concatenation Equal to Target | Medium | Solution |
| 2024 | Maximize the Confusion of an Exam | Medium | Solution |
| 2025 | Maximum Number of Ways to Partition an Array | Hard | Solution |
| 2027 | Minimum Moves to Convert String | Easy | Solution |
| 2028 | Find Missing Observations | Medium | Solution |
| 2029 | Stone Game IX | Medium | Solution |
| 2030 | Smallest K-Length Subsequence With Occurrences of a Letter | Hard | Solution |
| 2031 | Count Subarrays With More Ones Than Zeros | Medium | Solution |
| 2032 | Two Out of Three | Easy | Solution |
| 2033 | Minimum Operations to Make a Uni-Value Grid | Medium | Solution |
| 2034 | Stock Price Fluctuation | Medium | Solution |
| 2035 | Partition Array Into Two Arrays to Minimize Sum Difference | Hard | Solution |
| 2037 | Minimum Number of Moves to Seat Everyone | Easy | Solution |
| 2038 | Remove Colored Pieces if Both Neighbors are the Same Color | Medium | Solution |
| 2039 | The Time When the Network Becomes Idle | Medium | Solution |
| 2040 | Kth Smallest Product of Two Sorted Arrays | Hard | Solution |
| 2042 | Check if Numbers Are Ascending in a Sentence | Easy | Solution |
| 2043 | Simple Bank System | Medium | Solution |
| 2044 | Count Number of Maximum Bitwise-OR Subsets | Medium | Solution |
| 2045 | Second Minimum Time to Reach Destination | Hard | Solution |
| 2046 | Sort Linked List Already Sorted Using Absolute Values | Medium | Solution |
| 2047 | Number of Valid Words in a Sentence | Easy | Solution |
| 2048 | Next Greater Numerically Balanced Number | Medium | Solution |
| 2049 | Count Nodes With the Highest Score | Medium | Solution |
| 2050 | Parallel Courses III | Hard | Solution |
| 2053 | Kth Distinct String in an Array | Easy | Solution |
| 2054 | Two Best Non-Overlapping Events | Medium | Solution |
| 2055 | Plates Between Candles | Medium | Solution |
| 2056 | Number of Valid Move Combinations On Chessboard | Hard | Solution |
| 2057 | Smallest Index With Equal Value | Easy | Solution |
| 2058 | Find the Minimum and Maximum Number of Nodes Between Critical Points | Medium | Solution |
| 2059 | Minimum Operations to Convert Number | Medium | Solution |
| 2060 | Check if an Original String Exists Given Two Encoded Strings | Hard | Solution |
| 2062 | Count Vowel Substrings of a String | Easy | Solution |
| 2063 | Vowels of All Substrings | Medium | Solution |
| 2064 | Minimized Maximum of Products Distributed to Any Store | Medium | Solution |
| 2065 | Maximum Path Quality of a Graph | Hard | Solution |
| 2068 | Check Whether Two Strings are Almost Equivalent | Easy | Solution |
| 2069 | Walking Robot Simulation II | Medium | Solution |
| 2070 | Most Beautiful Item for Each Query | Medium | Solution |
| 2071 | Maximum Number of Tasks You Can Assign | Hard | Solution |
| 2073 | Time Needed to Buy Tickets | Easy | Solution |
| 2074 | Reverse Nodes in Even Length Groups | Medium | Solution |
| 2075 | Decode the Slanted Ciphertext | Medium | Solution |
| 2076 | Process Restricted Friend Requests | Hard | Solution |
| 2077 | Paths in Maze That Lead to Same Room | Medium | Solution |
| 2078 | Two Furthest Houses With Different Colors | Easy | Solution |
| 2079 | Watering Plants | Medium | Solution |
| 2080 | Range Frequency Queries | Medium | Solution |
| 2081 | Sum of k-Mirror Numbers | Hard | Solution |
| 2083 | Substrings That Begin and End With the Same Letter | Medium | Solution |
| 2085 | Count Common Words With One Occurrence | Easy | Solution |
| 2086 | Minimum Number of Buckets Required to Collect Rainwater from Houses | Medium | Solution |
| 2087 | Minimum Cost Homecoming of a Robot in a Grid | Medium | Solution |
| 2088 | Count Fertile Pyramids in a Land | Hard | Solution |
| 2089 | Find Target Indices After Sorting Array | Easy | Solution |
| 2090 | K Radius Subarray Averages | Medium | Solution |
| 2091 | Removing Minimum and Maximum From Array | Medium | Solution |
| 2092 | Find All People With Secret | Hard | Solution |
| 2093 | Minimum Cost to Reach City With Discounts | Medium | Solution |
| 2094 | Finding 3-Digit Even Numbers | Easy | Solution |
| 2095 | Delete the Middle Node of a Linked List | Medium | Solution |
| 2096 | Step-By-Step Directions From a Binary Tree Node to Another | Medium | Solution |
| 2097 | Valid Arrangement of Pairs | Hard | Solution |
| 2099 | Find Subsequence of Length K With the Largest Sum | Easy | Solution |
| 2100 | Find Good Days to Rob the Bank | Medium | Solution |
| 2101 | Detonate the Maximum Bombs | Medium | Solution |
| 2102 | Sequentially Ordinal Rank Tracker | Hard | Solution |
| 2103 | Rings and Rods | Easy | Solution |
| 2104 | Sum of Subarray Ranges | Medium | Solution |
| 2105 | Watering Plants II | Medium | Solution |
| 2106 | Maximum Fruits Harvested After at Most K Steps | Hard | Solution |
| 2107 | Number of Unique Flavors After Sharing K Candies | Medium | Solution |
| 2108 | Find First Palindromic String in the Array | Easy | Solution |
| 2109 | Adding Spaces to a String | Medium | Solution |
| 2110 | Number of Smooth Descent Periods of a Stock | Medium | Solution |
| 2111 | Minimum Operations to Make the Array K-Increasing | Hard | Solution |
| 2114 | Maximum Number of Words Found in Sentences | Easy | Solution |
| 2115 | Find All Possible Recipes from Given Supplies | Medium | Solution |
| 2119 | A Number After a Double Reversal | Easy | Solution |
| 2120 | Execution of All Suffix Instructions Staying in a Grid | Medium | Solution |
| 2121 | Intervals Between Identical Elements | Medium | Solution |
| 2122 | Recover the Original Array | Hard | Solution |
| 2124 | Check if All A's Appears Before All B's | Easy | Solution |
| 2125 | Number of Laser Beams in a Bank | Medium | Solution |
| 2126 | Destroying Asteroids | Medium | Solution |
| 2127 | Maximum Employees to Be Invited to a Meeting | Hard | Solution |
| 2128 | Remove All Ones With Row and Column Flips | Medium | Solution |
| 2129 | Capitalize the Title | Easy | Solution |
| 2130 | Maximum Twin Sum of a Linked List | Medium | Solution |
| 2131 | Longest Palindrome by Concatenating Two Letter Words | Medium | Solution |
| 2138 | Divide a String Into Groups of Size k | Easy | Solution |
| 2139 | Minimum Moves to Reach Target Score | Medium | Solution |
| 2140 | Solving Questions With Brainpower | Medium | Solution |
| 2144 | Minimum Cost of Buying Candies With Discount | Easy | Solution |
| 2145 | Count the Hidden Sequences | Medium | Solution |
| 2146 | K Highest Ranked Items Within a Price Range | Medium | Solution |
| 2147 | Number of Ways to Divide a Long Corridor | Hard | Solution |
| 2148 | Count Elements With Strictly Smaller and Greater Elements | Easy | Solution |
| 2149 | Rearrange Array Elements by Sign | Medium | Solution |
| 2150 | Find All Lonely Numbers in the Array | Medium | Solution |
| 2151 | Maximum Good People Based on Statements | Hard | Solution |
| 2154 | Keep Multiplying Found Values by Two | Easy | Solution |
| 2155 | All Divisions With the Highest Score of a Binary Array | Medium | Solution |
| 2156 | Find Substring With Given Hash Value | Hard | Solution |
| 2157 | Groups of Strings | Hard | Solution |
| 2160 | Minimum Sum of Four Digit Number After Splitting Digits | Easy | Solution |
| 2161 | Partition Array According to Given Pivot | Medium | Solution |
| 2162 | Minimum Cost to Set Cooking Time | Medium | Solution |
| 2163 | Minimum Difference in Sums After Removal of Elements | Hard | Solution |
| 2164 | Sort Even and Odd Indices Independently | Easy | Solution |
| 2165 | Smallest Value of the Rearranged Number | Medium | Solution |
| 2166 | Design Bitset | Medium | Solution |
| 2167 | Minimum Time to Remove All Cars Containing Illegal Goods | Hard | Solution |
| 2168 | Unique Substrings With Equal Digit Frequency | Medium | Solution |
| 2169 | Count Operations to Obtain Zero | Easy | Solution |
| 2170 | Minimum Operations to Make the Array Alternating | Medium | Solution |
| 2171 | Removing Minimum Number of Magic Beans | Medium | Solution |
| 2172 | Maximum AND Sum of Array | Hard | Solution |
| 2176 | Count Equal and Divisible Pairs in an Array | Easy | Solution |
| 2177 | Find Three Consecutive Integers That Sum to a Given Number | Medium | Solution |
| 2178 | Maximum Split of Positive Even Integers | Medium | Solution |
| 2179 | Count Good Triplets in an Array | Hard | Solution |
| 2180 | Count Integers With Even Digit Sum | Easy | Solution |
| 2181 | Merge Nodes in Between Zeros | Medium | Solution |
| 2182 | Construct String With Repeat Limit | Medium | Solution |
| 2183 | Count Array Pairs Divisible by K | Hard | Solution |
| 2185 | Counting Words With a Given Prefix | Easy | Solution |
| 2186 | Minimum Number of Steps to Make Two Strings Anagram II | Medium | Solution |
| 2187 | Minimum Time to Complete Trips | Medium | Solution |
| 2188 | Minimum Time to Finish the Race | Hard | Solution |
| 2189 | Number of Ways to Build House of Cards | Medium | Solution |
| 2190 | Most Frequent Number Following Key In an Array | Easy | Solution |
| 2191 | Sort the Jumbled Numbers | Medium | Solution |
| 2192 | All Ancestors of a Node in a Directed Acyclic Graph | Medium | Solution |
| 2193 | Minimum Number of Moves to Make Palindrome | Hard | Solution |
| 2194 | Cells in a Range on an Excel Sheet | Easy | Solution |
| 2195 | Append K Integers With Minimal Sum | Medium | Solution |
| 2196 | Create Binary Tree From Descriptions | Medium | Solution |
| 2197 | Replace Non-Coprime Numbers in Array | Hard | Solution |
| 2200 | Find All K-Distant Indices in an Array | Easy | Solution |
| 2201 | Count Artifacts That Can Be Extracted | Medium | Solution |
| 2202 | Maximize the Topmost Element After K Moves | Medium | Solution |
| 2203 | Minimum Weighted Subgraph With the Required Paths | Hard | Solution |
| 2206 | Divide Array Into Equal Pairs | Easy | Solution |
| 2207 | Maximize Number of Subsequences in a String | Medium | Solution |
| 2208 | Minimum Operations to Halve Array Sum | Medium | Solution |
| 2209 | Minimum White Tiles After Covering With Carpets | Hard | Solution |
| 2210 | Count Hills and Valleys in an Array | Easy | Solution |
| 2211 | Count Collisions on a Road | Medium | Solution |
| 2212 | Maximum Points in an Archery Competition | Medium | Solution |
| 2214 | Minimum Health to Beat Game | Medium | Solution |
| 2215 | Find the Difference of Two Arrays | Easy | Solution |
| 2216 | Minimum Deletions to Make Array Beautiful | Medium | Solution |
| 2217 | Find Palindrome With Fixed Length | Medium | Solution |
| 2218 | Maximum Value of K Coins From Piles | Hard | Solution |
| 2220 | Minimum Bit Flips to Convert Number | Easy | Solution |
| 2221 | Find Triangular Sum of an Array | Medium | Solution |
| 2222 | Number of Ways to Select Buildings | Medium | Solution |
| 2224 | Minimum Number of Operations to Convert Time | Easy | Solution |
| 2225 | Find Players With Zero or One Losses | Medium | Solution |
| 2226 | Maximum Candies Allocated to K Children | Medium | Solution |
| 2227 | Encrypt and Decrypt Strings | Hard | Solution |
| 2229 | Check if an Array Is Consecutive | Easy | Solution |
| 2231 | Largest Number After Digit Swaps by Parity | Easy | Solution |
| 2232 | Minimize Result by Adding Parentheses to Expression | Medium | Solution |
| 2233 | Maximum Product After K Increments | Medium | Solution |
| 2235 | Add Two Integers | Easy | Solution |
| 2236 | Root Equals Sum of Children | Easy | Solution |
| 2239 | Find Closest Number to Zero | Easy | Solution |
| 2240 | Number of Ways to Buy Pens and Pencils | Medium | Solution |
| 2241 | Design an ATM Machine | Medium | Solution |
| 2243 | Calculate Digit Sum of a String | Easy | Solution |
| 2244 | Minimum Rounds to Complete All Tasks | Medium | Solution |
| 2255 | Count Prefixes of a Given String | Easy | Solution |
| 2305 | Fair Distribution of Cookies | Medium | Solution |
FAQ
Space Complexity
I always only estimate the extra space excluding the space taken by the answer.
This is because the space for the answer is needed anyway for all algorithms of the same problem and it is the extra space that tells good algorithms apart from bad ones.
For example, assume a problem's answer always takes O(N^2) space. Algorithm A takes O(1) extra space, algorithm B takes O(N) extra space, and algorithm C takes O(N^2) extra space.
Which algorithm is better from space complexity perspective? Definitely algorithm A is the best, algorithm B is the second and algorithm C is the worst.
But if we take the answer space into account, all these three algorithms have the same O(N^2) space complexity overall.
So, only estimating the extra space excluding the answer space helps us better understand the algorithm's overhead.
License
All rights reserved by github.com/lzl124631x. Contact me if you want to redistribute the code. No commercial use.