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目录
| index | title | code | Difficulty |
|---|---|---|---|
| 1 | A + B Problem | JavaScript | Easy |
| 2 | Trailing Zeros | JavaScript | Easy |
| 3 | Digit Counts | Medium | |
| 4 | Ugly Number II | JavaScript | Medium |
| 5 | Kth Largest Element | Medium | |
| 6 | Merge Two Sorted Arrays | JavaScript | Easy |
| 7 | Serialize and Deserialize Binary Tree | Python | Medium |
| 8 | Rotate String | Python | Easy |
| 9 | Fizz Buzz | JavaScript | Easy |
| 10 | String Permutation II | Medium | |
| 11 | Search Range in Binary Search Tree | Python | Medium |
| 12 | Min Stack | Python | Medium |
| 13 | Implement strStr() | Easy | |
| 14 | First Position of Target | JavaScript | Easy |
| 15 | Permutations | Python | Medium |
| 16 | Permutations II | Python | Medium |
| 17 | Subsets | Python | Medium |
| 18 | Subsets II | Python | Medium |
| 20 | Dices Sum | Python | Hard |
| 21 | Moving Circle | Medium | |
| 22 | Flatten List | Python | Easy |
| 24 | LFU Cache | Python | Hard |
| 26 | inner product | Hard | |
| 27 | abc String | Hard | |
| 28 | Search a 2D Matrix | JavaScript | Easy |
| 29 | Interleaving String | Medium | |
| 30 | Insert Interval | Medium | |
| 31 | Partition Array | Medium | |
| 32 | Minimum Window Substring | Python | Medium |
| 33 | N-Queens | Medium | |
| 34 | N-Queens II | Medium | |
| 35 | Reverse Linked List | JavaScript | Easy |
| 36 | Reverse Linked List II | JavaScript | Medium |
| 37 | Reverse 3-digit Integer | JavaScript | Naive |
| 38 | Search a 2D Matrix II | JavaScript | Medium |
| 39 | Recover Rotated Sorted Array | JavaScript | Easy |
| 40 | Implement Queue by Two Stacks | Python | Medium |
| 41 | Maximum Subarray | JavaScript | Easy |
| 42 | Maximum Subarray II | Python | Medium |
| 43 | Maximum Subarray III | JavaScript | Hard |
| 44 | Minimum Subarray | Python | Easy |
| 45 | Maximum Subarray Difference | JavaScript | Medium |
| 46 | Majority Element | Python | Easy |
| 47 | Majority Element II | Python | Medium |
| 48 | Majority Number III | JavaScript | Medium |
| 49 | Sort Letters by Case | Python | Medium |
| 50 | Product of Array Exclude Itself | Python | Easy |
| 51 | Previous Permutation | Medium | |
| 52 | Next Permutation | Medium | |
| 53 | Reverse Words in a String | Python | Easy |
| 54 | String to Integer (atoi) | Hard | |
| 55 | Compare Strings | JavaScript | Easy |
| 56 | Two Sum | JavaScript | Easy |
| 57 | 3Sum | Python | Medium |
| 58 | 4Sum | JavaScript Python | Medium |
| 59 | 3Sum Closest | JavaScript | Medium |
| 60 | Search Insert Position | JavaScript | Easy |
| 61 | Search for a Range | JavaScript | Medium |
| 62 | Search in Rotated Sorted Array | JavaScript | Medium |
| 63 | Search in Rotated Sorted Array II | JavaScript | Medium |
| 64 | Merge Sorted Array | Python | Easy |
| 65 | Median of two Sorted Arrays | Hard | |
| 66 | Binary Tree Preorder Traversal | JavaScript | Easy |
| 67 | Binary Tree Inorder Traversal | JavaScript | Easy |
| 68 | Binary Tree Postorder Traversal | JavaScript | Easy |
| 69 | Binary Tree Level Order Traversal | JavaScript | Easy |
| 70 | Binary Tree Level Order Traversal II | Python | Medium |
| 71 | Binary Tree Zigzag Level Order Traversal | JavaScript | Medium |
| 72 | Construct Binary Tree from Inorder and Postorder Traversal | JavaScript | Medium |
| 73 | Construct Binary Tree from Preorder and Inorder Traversal | JavaScript | Medium |
| 74 | First Bad Version | Python | Medium |
| 75 | Find Peak Element | Python | Medium |
| 76 | Longest Increasing Subsequence | JavaScript | Medium |
| 77 | Longest Common Subsequence | JavaScript | Medium |
| 78 | Longest Common Prefix | Medium | |
| 79 | Longest Common Substring | JavaScript | Medium |
| 80 | Median | Easy | |
| 81 | Find Median from Data Stream | Hard | |
| 82 | Single Number | JavaScript | Easy |
| 83 | Single Number II | JavaScript | Medium |
| 84 | Single Number III | Python | Medium |
| 85 | Insert Node in a Binary Search Tree | Python | Easy |
| 86 | Binary Search Tree Iterator | Python | Hard |
| 87 | Remove Node in Binary Search Tree | Python | Hard |
| 88 | Lowest Common Ancestor of a Binary Tree | Python | Medium |
| 89 | k Sum | Hard | |
| 90 | k Sum II | Python | Medium |
| 91 | Minimum Adjustment Cost | Medium | |
| 92 | Backpack | JavaScript | Medium |
| 93 | Balanced Binary Tree | JavaScript | Easy |
| 94 | Binary Tree Maximum Path Sum | JavaScript | Medium |
| 95 | Validate Binary Search Tree | JavaScript | Medium |
| 96 | Partition List | JavaScript | Easy |
| 97 | Maximum Depth of Binary Tree | JavaScript | Easy |
| 98 | Sort List | Python | Medium |
| 99 | Reorder List | Python | Medium |
| 100 | Remove Duplicates from Sorted Array | Python | Easy |
| 101 | Remove Duplicates from Sorted Array II | Python | Easy |
| 102 | Linked List Cycle | Python | Medium |
| 103 | Linked List Cycle II | Python | Hard |
| 104 | Merge K Sorted Lists | Python | Medium |
| 105 | Copy List with Random Pointer | Python | Medium |
| 106 | Convert Sorted List to Binary Search Tree | Python | Medium |
| 107 | Word Break | Medium | |
| 108 | Palindrome Partitioning II | Medium | |
| 109 | Triangle | JavaScript | Medium |
| 110 | Minimum Path Sum | JavaScript | Easy |
| 111 | Climbing Stairs | JavaScript | Easy |
| 112 | Remove Duplicates from Sorted List | JavaScript | Easy |
| 113 | Remove Duplicates from Sorted List II | Python | Medium |
| 114 | Unique Paths | JavaScript | Easy |
| 115 | Unique Paths II | JavaScript | Easy |
| 116 | Jump Game | JavaScript | Medium |
| 117 | Jump Game II | JavaScript | Medium |
| 118 | Distinct Subsequences | Python | Medium |
| 119 | Edit Distance | Medium | |
| 120 | Word Ladder | Hard | |
| 121 | Word Ladder II | Hard | |
| 122 | Largest Rectangle in Histogram | Hard | |
| 123 | Word Search | Medium | |
| 124 | Longest Consecutive Sequence | Medium | |
| 125 | Backpack II | JavaScript | Medium |
| 126 | Max Tree | Hard | |
| 127 | Topological Sorting | Medium | |
| 128 | Hash Function | JavaScript | Easy |
| 129 | Rehashing | Medium | |
| 130 | Heapify | Python | Medium |
| 131 | The Skyline Problem | Super | |
| 132 | Word Search II | Hard | |
| 133 | Longest Word | Python | Easy |
| 134 | LRU Cache | Python | Hard |
| 135 | Combination Sum | Python | Medium |
| 136 | Palindrome Partitioning | Medium | |
| 137 | Clone Graph | Medium | |
| 138 | Subarray Sum | Python | Easy |
| 139 | Subarray Sum Closest | Medium | |
| 140 | Fast Power | Python | Medium |
| 141 | Sqrt(x) | Python | Easy |
| 142 | O(1) Check Power of 2 | JavaScript | Easy |
| 143 | Sort Colors II | Medium | |
| 144 | Interleaving Positive and Negative Numbers | Python | Medium |
| 145 | Lowercase to Uppercase | JavaScript | Naive |
| 146 | Lowercase to Uppercase II | Naive | |
| 147 | Narcissistic Number | Easy | |
| 148 | Sort Colors | Medium | |
| 149 | Best Time to Buy and Sell Stock | JavaScript | Medium |
| 150 | Best Time to Buy and Sell Stock II | JavaScript | Medium |
| 151 | Best Time to Buy and Sell Stock III | JavaScript | Medium |
| 152 | Combinations | Python | Medium |
| 153 | Combination Sum II | Python | Medium |
| 154 | Regular Expression Matching | Hard | |
| 155 | Minimum Depth of Binary Tree | JavaScript | Easy |
| 156 | Merge Intervals | Easy | |
| 157 | Unique Characters | Python | Easy |
| 158 | Valid Anagram | JavaScript | Easy |
| 159 | Find Minimum in Rotated Sorted Array | JavaScript | Medium |
| 160 | Find Minimum in Rotated Sorted Array II | JavaScript | Medium |
| 161 | Rotate Image | JavaScript | Medium |
| 162 | Set Matrix Zeroes | JavaScript | Medium |
| 163 | Unique Binary Search Trees | JavaScript | Medium |
| 164 | Unique Binary Search Trees II | Python | Medium |
| 165 | Merge Two Sorted Lists | JavaScript | Easy |
| 166 | Nth to Last Node in List | Python | Easy |
| 167 | Add Two Numbers | JavaScript | Easy |
| 168 | Burst Balloons | Hard | |
| 169 | Tower of Hanoi | Medium | |
| 170 | Rotate List | JavaScript | Medium |
| 171 | Anagrams | JavaScript | Medium |
| 172 | Remove Element | Python | Easy |
| 173 | Insertion Sort List | Python | Easy |
| 174 | Remove Nth Node From End of List | JavaScript | Easy |
| 175 | Invert Binary Tree | JavaScript | Easy |
| 176 | Route Between Two Nodes in Graph | Medium | |
| 177 | Convert Sorted Array to Binary Search Tree With Minimal Height. | Python | Easy |
| 178 | Graph Valid Tree | Medium | |
| 179 | Update Bits | Medium | |
| 181 | Flip Bits | JavaScript | Easy |
| 182 | Delete Digits | Medium | |
| 183 | Wood Cut | Hard | |
| 184 | Largest Number | Medium | |
| 185 | Matrix Zigzag Traversal | JavaScript | Easy |
| 186 | Max Points on a Line | Medium | |
| 187 | Gas Station | Medium | |
| 188 | Insert five | Easy | |
| 189 | First Missing Positive | JavaScript | Medium |
| 190 | Next Permutation II | Medium | |
| 191 | Maximum Product Subarray | JavaScript | Medium |
| 192 | Wildcard Matching | Hard | |
| 193 | Longest Valid Parentheses | JavaScript | Easy |
| 194 | Find Words | Medium | |
| 196 | Missing Number | JavaScript | Medium |
| 197 | Permutation Index | Medium | |
| 198 | Permutation Index II | Medium | |
| 199 | Judge Connection | Medium | |
| 200 | Longest Palindromic Substring | Medium | |
| 201 | Segment Tree Build | Python | Medium |
| 202 | Segment Tree Query | Python | Medium |
| 203 | Segment Tree Modify | Python | Medium |
| 204 | Singleton | Python | Easy |
| 205 | Interval Minimum Number | Python | Medium |
| 206 | Interval Sum | Python | Medium |
| 207 | Interval Sum II | Python | Hard |
| 208 | Assignment Operator Overloading (C++ Only) | Medium | |
| 209 | First Unique Character in a String | JavaScript | Easy |
| 210 | Null-terminated String | Easy | |
| 211 | String Permutation | JavaScript | Easy |
| 212 | Space Replacement | Python | Easy |
| 213 | String Compression | JavaScript | Easy |
| 214 | Max of Array | Naive | |
| 215 | Rate Limiter | Hard | |
| 216 | Substring Rotation | Easy | |
| 217 | Remove Duplicates from Unsorted List | Easy | |
| 218 | Student Level | Easy | |
| 219 | Insert Node in Sorted Linked List | Easy | |
| 221 | Add Two Numbers II | JavaScript | Medium |
| 222 | Setter and Getter | Naive | |
| 223 | Palindrome Linked List | JavaScript | Medium |
| 224 | Implement Three Stacks by Single Array | Medium | |
| 225 | Find Node in Linked List | Naive | |
| 226 | Set of Stacks II | Hard | |
| 227 | Mock Hanoi Tower by Stacks | Easy | |
| 228 | Middle of Linked List | Naive | |
| 229 | Stack Sorting | Medium | |
| 230 | Animal Shelter | Hard | |
| 231 | Typeahead | Hard | |
| 232 | Tiny Url | Medium | |
| 233 | Next Smaller and Larger Number with the Same 1 Bits | Medium | |
| 234 | Web Crawler | Super | |
| 235 | Prime Factorization | Easy | |
| 236 | Swap Bits | Easy | |
| 237 | Missing Integer | Easy | |
| 238 | Monochrome Screen | Easy | |
| 239 | Root of Equation | Easy | |
| 240 | Program Check | Hard | |
| 241 | String to Integer | Naive | |
| 242 | Convert Binary Tree to Linked Lists by Depth | Python | Easy |
| 243 | Amicable Pair | Easy | |
| 244 | Delete Char | Medium | |
| 245 | Subtree | Medium | |
| 246 | Binary Tree Path Sum II | Medium | |
| 247 | Segment Tree Query II | Python | Medium |
| 248 | Count of Smaller Number | JavaScript | Medium |
| 249 | Count of Smaller Number before itself | JavaScript | Hard |
| 250 | Special Palindrome String | Easy | |
| 251 | Array compression | Medium | |
| 252 | arithmetic matrix | Medium | |
| 253 | Minimum Type Way | Medium | |
| 254 | Drop Eggs | Easy | |
| 255 | Multi-string search | Easy | |
| 256 | The Maximum Order | Hard | |
| 257 | Longest String Chain | Medium | |
| 258 | Map Jump | Hard | |
| 259 | Find the largest Divisor | Medium | |
| 260 | Same Diagonal Elements | Easy | |
| 261 | Maximum Connected Area | Medium | |
| 262 | heir tree | Medium | |
| 263 | Matching of parentheses | Easy | |
| 264 | Counting Universal Subarrays | Easy | |
| 265 | Maximum Non-Negative Subarray | Easy | |
| 266 | Expect Distance | Medium | |
| 267 | minimum rest days | Medium | |
| 268 | Parentheses Score | Medium | |
| 269 | two colors' tower | Hard | |
| 270 | Letter Combinations of a Phone Number II | Medium | |
| 271 | prefix notation to postfix notation | Medium | |
| 272 | Climbing Stairs II | Easy | |
| 273 | Test Strategy | Medium | |
| 274 | Make binary tree average | Super | |
| 275 | Moving Shed | Medium | |
| 276 | another zuma | Medium | |
| 277 | Word Spacing | Easy | |
| 278 | Paint Fill | JavaScript | Easy |
| 279 | Number of Ways to Represent N Cents | Medium | |
| 280 | Closest City | Easy | |
| 281 | Paint the Ceiling | Medium | |
| 282 | Decrypt the String | Easy | |
| 283 | Max of 3 Numbers | JavaScript | Naive |
| 284 | Matching Subsequences | Medium | |
| 285 | Tall Building | Medium | |
| 286 | Inversions | Hard | |
| 287 | The Competition of View | Medium | |
| 290 | Sorted Arrangement | Hard | |
| 291 | Second Diameter | Medium | |
| 292 | Sort Anagrams Array | Easy | |
| 293 | The depth of the tunnel | Medium | |
| 294 | Linked List Simplification | Easy | |
| 295 | Intersection | Easy | |
| 296 | Unique Array | Easy | |
| 297 | Find the maximum | Naive | |
| 298 | Find prime | Naive | |
| 300 | Meeting Room IV | Medium | |
| 301 | Lucky Number II | Hard | |
| 302 | Digital Pairing | Easy | |
| 303 | Beautiful Number | Medium | |
| 304 | Maximum product | Medium | |
| 306 | Product List | Easy | |
| 307 | Transform String | Medium | |
| 308 | Sepcial Substring | Medium | |
| 309 | Interleaved Array | Easy | |
| 310 | Digital distortion | Easy | |
| 311 | Pioneering palindrome | Easy | |
| 312 | Bull Cards | Medium | |
| 313 | Minimum Insertion | Hard | |
| 314 | The Lost Record | Medium | |
| 315 | Reformat String | Medium | |
| 316 | Combination set | Easy | |
| 317 | Minimum Parentheses Matching | Medium | |
| 318 | Character Grid | Easy | |
| 319 | Square Queue | Hard | |
| 321 | perfect string | Easy | |
| 322 | Chess Game | Easy | |
| 323 | string game | Easy | |
| 324 | Regular Expression Search | Hard | |
| 325 | Football | Medium | |
| 326 | Slide Soduku | Easy | |
| 327 | Distance Metrics | Medium | |
| 328 | String Partition | Medium | |
| 329 | Double Array | Easy | |
| 330 | Increasing Number | Medium | |
| 331 | Confusing Number | Medium | |
| 332 | restoreArray | Hard | |
| 333 | Identifying Strings | Easy | |
| 334 | Order Check | Easy | |
| 335 | plateau | Medium | |
| 336 | Text Compression | Easy | |
| 337 | Team notification | Medium | |
| 339 | Median II | Medium | |
| 340 | Red and Black Chess | Hard | |
| 342 | Valley sequence | Medium | |
| 343 | Circle | Easy | |
| 344 | Song Time | Hard | |
| 346 | xorsum of Interval extremum | Hard | |
| 347 | maximum number expectation | Hard | |
| 348 | TrackSwitching | Medium | |
| 349 | Developer-Tester Integration | Hard | |
| 352 | PrettyPrint | Easy | |
| 353 | Largest letter | Easy | |
| 354 | lottery draw | Hard | |
| 355 | shuttleInBuildings | Hard | |
| 357 | Symmetrical Suffix | Medium | |
| 358 | treePlanning | Easy | |
| 359 | makeEquilateralTriangle | Easy | |
| 360 | Sliding Window Median | Hard | |
| 362 | Sliding Window Maximum | JavaScript | Hard |
| 363 | Trapping Rain Water | Medium | |
| 364 | Trapping Rain Water II | Hard | |
| 365 | Count 1 in Binary | Python | Easy |
| 366 | Fibonacci | JavaScript | Naive |
| 367 | Expression Tree Build | Hard | |
| 368 | Expression Evaluation | Hard | |
| 369 | Convert Expression to Polish Notation | Medium | |
| 370 | Convert Expression to Reverse Polish Notation | Medium | |
| 371 | Print Numbers by Recursion | JavaScript | Medium |
| 372 | Delete Node in a Linked List | Python | Easy |
| 373 | Partition Array by Odd and Even | Python | Easy |
| 374 | Spiral Matrix | JavaScript | Medium |
| 375 | Clone Binary Tree | JavaScript | Easy |
| 376 | Binary Tree Path Sum | Python | Easy |
| 378 | Convert Binary Tree to Doubly Linked List | Python | Medium |
| 379 | Reorder array to construct the minimum number | Medium | |
| 380 | Intersection of Two Linked Lists | Python | Medium |
| 381 | Spiral Matrix II | Medium | |
| 382 | Triangle Count | Medium | |
| 383 | Container With Most Water | Medium | |
| 384 | Longest Substring Without Repeating Characters | JavaScript | Medium |
| 385 | ArrayList | Easy | |
| 386 | Longest Substring with At Most K Distinct Characters | Medium | |
| 387 | The Smallest Difference | JavaScript | Medium |
| 388 | Permutation Sequence | Medium | |
| 389 | Valid Sudoku | Easy | |
| 390 | Find Peak Element II | Hard | |
| 391 | Number of Airplanes in the Sky | Medium | |
| 392 | House Robber | JavaScript | Medium |
| 393 | Best Time to Buy and Sell Stock IV | JavaScript | Medium |
| 394 | Coins in a Line | Medium | |
| 395 | Coins in a Line II | Medium | |
| 396 | Coins in a Line III | Hard | |
| 397 | Longest Continuous Increasing Subsequence | JavaScript | Easy |
| 398 | Longest Continuous Increasing Subsequence II | Hard | |
| 399 | Nuts & Bolts Problem | Medium | |
| 400 | Maximum Gap | Medium | |
| 401 | Kth Smallest Number in Sorted Matrix | JavaScript | Medium |
| 402 | Continuous Subarray Sum | JavaScript | Medium |
| 403 | Continuous Subarray Sum II | Medium | |
| 404 | Subarray Sum II | Medium | |
| 405 | Submatrix Sum | Medium | |
| 406 | Minimum Size Subarray Sum | JavaScript | Medium |
| 407 | Plus One | JavaScript | Easy |
| 408 | Add Binary | JavaScript | Easy |
| 411 | Gray Code | Medium | |
| 412 | Candy | Medium | |
| 413 | Reverse Integer | JavaScript | Easy |
| 414 | Divide Two Integers | Medium | |
| 415 | Valid Palindrome | JavaScript | Medium |
| 417 | Valid Number | Easy | |
| 418 | Integer to Roman | JavaScript | Medium |
| 419 | Roman to Integer | JavaScript | Medium |
| 420 | Count and Say | Easy | |
| 421 | Simplify Path | Medium | |
| 422 | Length of Last Word | JavaScript | Easy |
| 423 | Valid Parentheses | JavaScript | Easy |
| 424 | Evaluate Reverse Polish Notation | Python | Medium |
| 425 | Letter Combinations of a Phone Number | JavaScript | Medium |
| 426 | Restore IP Addresses | JavaScript | Medium |
| 427 | Generate Parentheses | JavaScript | Medium |
| 428 | Pow(x, n) | Python | Medium |
| 430 | Scramble String | Hard | |
| 431 | Connected Component in Undirected Graph | Medium | |
| 432 | Find the Weak Connected Component in the Directed Graph | Medium | |
| 433 | Number of Islands | JavaScript | Easy |
| 434 | Number of Islands II | Medium | |
| 435 | Post Office Problem | Hard | |
| 436 | Maximal Square | JavaScript | Medium |
| 437 | Copy Books | Medium | |
| 438 | Copy Books II | Hard | |
| 439 | Segment Tree Build II | Python | Medium |
| 440 | Backpack III | Medium | |
| 442 | Implement Trie (Prefix Tree) | Python | Medium |
| 443 | Two Sum - Greater than target | Medium | |
| 444 | graph valid tree II | Medium | |
| 445 | Cosine Similarity | Python | Easy |
| 447 | Search in a Big Sorted Array | Medium | |
| 448 | Inorder Successor in BST | Python | Medium |
| 449 | Char to Integer | Naive | |
| 450 | Reverse Nodes in k-Group | JavaScript | Hard |
| 451 | Swap Nodes in Pairs | JavaScript | Easy |
| 452 | Remove Linked List Elements | JavaScript | Easy |
| 453 | Flatten Binary Tree to Linked List | JavaScript | Easy |
| 454 | Rectangle Area | Python | Naive |
| 455 | Student ID | Easy | |
| 456 | Reference | Naive | |
| 457 | Classical Binary Search | Python | Easy |
| 458 | Last Position of Target | Easy | |
| 459 | Closest Number in Sorted Array | Easy | |
| 460 | Find K Closest Elements | JavaScript | Medium |
| 461 | Kth Smallest Numbers in Unsorted Array | Medium | |
| 462 | Total Occurrence of Target | Easy | |
| 463 | Sort Integers | JavaScript | Naive |
| 464 | Sort Integers II | JavaScript | Easy |
| 465 | Kth Smallest Sum In Two Sorted Arrays | Hard | |
| 466 | Count Linked List Nodes | JavaScript | Naive |
| 467 | Complete Binary Tree | Easy | |
| 468 | Symmetric Binary Tree | Easy | |
| 469 | Same Tree | JavaScript | Easy |
| 470 | Tweaked Identical Binary Tree | Easy | |
| 471 | Top K Frequent Words | JavaScript | Medium |
| 472 | Binary Tree Path Sum III | Hard | |
| 473 | Add and Search Word - Data structure design | Medium | |
| 474 | Lowest Common Ancestor II | Python | Easy |
| 475 | Binary Tree Maximum Path Sum II | Medium | |
| 476 | Stone Game | JavaScript | Medium |
| 477 | Surrounded Regions | Python | Medium |
| 478 | Simple Calculator | Naive | |
| 479 | Second Max of Array | JavaScript | Easy |
| 480 | Binary Tree Paths | JavaScript | Easy |
| 481 | Binary Tree Leaf Sum | Easy | |
| 482 | Binary Tree Level Sum | Easy | |
| 483 | Convert Linked List to Array List | Naive | |
| 484 | Swap Two Integers in Array | JavaScript | Naive |
| 485 | Generate ArrayList with Given Size | Naive | |
| 486 | Merge K Sorted Arrays | JavaScript | Medium |
| 487 | Name Deduplication | Easy | |
| 488 | Happy Number | JavaScript | Easy |
| 489 | Convert Array List to Linked List | Easy | |
| 490 | Set of Stacks | Easy | |
| 491 | Palindrome Number | JavaScript | Easy |
| 492 | Implement Queue by Linked List | Easy | |
| 493 | Implement Queue by Linked List II | Easy | |
| 494 | Implement Stack by Two Queues | Easy | |
| 495 | Implement Stack | Python | Easy |
| 496 | Toy Factory | Python | Easy |
| 497 | Shape Factory | Easy | |
| 498 | Parking Lot | Hard | |
| 499 | Word Count (Map Reduce) | Medium | |
| 500 | Inverted Index | Medium | |
| 501 | Design Twitter | Medium | |
| 502 | Mini Cassandra | Medium | |
| 503 | Anagram (Map Reduce) | Medium | |
| 504 | Inverted Index (Map Reduce) | Medium | |
| 505 | Web Logger | Medium | |
| 506 | Movie Recommendation | Easy | |
| 507 | Wiggle Sort II | Hard | |
| 508 | Wiggle Sort | Medium | |
| 509 | Mini Yelp | Hard | |
| 510 | Maximal Rectangle | Hard | |
| 511 | Swap Two Nodes in Linked List | JavaScript | Medium |
| 512 | Decode Ways | JavaScript | Medium |
| 513 | Perfect Squares | JavaScript | Medium |
| 514 | Paint Fence | Easy | |
| 515 | Paint House | Medium | |
| 516 | Paint House II | Hard | |
| 517 | Ugly Number | JavaScript | Easy |
| 518 | Super Ugly Number | JavaScript | Medium |
| 519 | Consistent Hashing | Easy | |
| 520 | Consistent Hashing II | Medium | |
| 521 | Remove Duplicate Numbers in Array | Easy | |
| 522 | Tiny Url II | Medium | |
| 523 | Url Parser | Medium | |
| 524 | Left Pad | Python | Easy |
| 525 | Mini Uber | Medium | |
| 526 | Load Balancer | Medium | |
| 527 | Trie Serialization | Hard | |
| 528 | Flatten Nested List Iterator | Python | Medium |
| 529 | Geohash | Medium | |
| 530 | Geohash II | Medium | |
| 531 | Six Degrees | Medium | |
| 532 | Reverse Pairs | JavaScript | Medium |
| 533 | Two Sum - Closest to target | Medium | |
| 534 | House Robber II | JavaScript | Medium |
| 535 | House Robber III | Medium | |
| 537 | N-Gram (Map Reduce) | Medium | |
| 538 | Memcache | Medium | |
| 539 | Move Zeroes | JavaScript | Easy |
| 540 | Zigzag Iterator | Python | Medium |
| 541 | Zigzag Iterator II | Medium | |
| 543 | Kth Largest in N Arrays | Hard | |
| 544 | Top k Largest Numbers | Medium | |
| 545 | Top k Largest Numbers II | Medium | |
| 546 | Implement Queue by Interface | Easy | |
| 547 | Intersection of Two Arrays | Python | Easy |
| 548 | Intersection of Two Arrays II | JavaScript | Medium |
| 549 | Top K Frequent Words (Map Reduce) | Medium | |
| 550 | Top K Frequent Words II | Hard | |
| 551 | Nested List Weight Sum | Python | Easy |
| 552 | Create Maximum Number | Hard | |
| 553 | Bomb Enemy | Medium | |
| 554 | Sort Integers (Map Reduce) | Medium | |
| 555 | Counting Bloom Filter | Medium | |
| 556 | Standard Bloom Filter | Medium | |
| 557 | Count Characters | Easy | |
| 558 | Sliding Window Matrix Maximum | Hard | |
| 559 | Trie Service | Medium | |
| 560 | Friendship Service | Easy | |
| 561 | Array Distance | Hard | |
| 562 | Backpack IV | JavaScript | Medium |
| 563 | Backpack V | JavaScript | Medium |
| 564 | Combination Sum IV | JavaScript | Medium |
| 565 | Heart Beat | Medium | |
| 566 | GFS Client | Medium | |
| 567 | maximum score | Medium | |
| 568 | Three Chances | Medium | |
| 569 | Add Digits | JavaScript | Easy |
| 570 | Find the Missing Number II | Medium | |
| 572 | Music Pairs | Easy | |
| 573 | Build Post Office II | Hard | |
| 574 | Build Post Office | Medium | |
| 575 | Decode String | Medium | |
| 576 | Split Array | Easy | |
| 577 | Merge K Sorted Interval Lists | Medium | |
| 578 | Lowest Common Ancestor III | Python | Medium |
| 581 | Longest Repeating Subsequence | Medium | |
| 582 | Word Break II | Hard | |
| 584 | Drop Eggs II | Medium | |
| 585 | Maximum Number in Mountain Sequence | JavaScript | Medium |
| 586 | Sqrt(x) II | Medium | |
| 587 | Two Sum - Unique pairs | Medium | |
| 588 | Partition Equal Subset Sum | JavaScript | Medium |
| 589 | Connecting Graph | Medium | |
| 590 | Connecting Graph II | Medium | |
| 591 | Connecting Graph III | Medium | |
| 593 | Stone Game II | Medium | |
| 594 | strStr II | Hard | |
| 595 | Binary Tree Longest Consecutive Sequence | JavaScript | Easy |
| 596 | Minimum Subtree | Easy | |
| 597 | Subtree with Maximum Average | Easy | |
| 598 | Zombie in Matrix | Medium | |
| 599 | Insert into a Cyclic Sorted List | Medium | |
| 600 | Smallest Rectangle Enclosing Black Pixels | Hard | |
| 601 | Flatten 2D Vector | Python | Medium |
| 602 | Russian Doll Envelopes | Hard | |
| 603 | Largest Divisible Subset | Medium | |
| 604 | Window Sum | JavaScript | Easy |
| 605 | Sequence Reconstruction | Medium | |
| 606 | Kth Largest Element II | Medium | |
| 607 | Two Sum III - Data structure design | Python | Easy |
| 608 | Two Sum II - Input array is sorted | JavaScript | Medium |
| 609 | Two Sum - Less than or equal to target | Medium | |
| 610 | Two Sum - Difference equals to target | Medium | |
| 611 | Knight Shortest Path | Medium | |
| 612 | K Closest Points | Medium | |
| 613 | High Five | Medium | |
| 614 | Binary Tree Longest Consecutive Sequence II | JavaScript | Medium |
| 615 | Course Schedule | Medium | |
| 616 | Course Schedule II | Medium | |
| 617 | Maximum Average Subarray II | Medium | |
| 618 | Search Graph Nodes | Medium | |
| 619 | Binary Tree Longest Consecutive Sequence III | Medium | |
| 620 | Maximum Subarray IV | Medium | |
| 621 | Maximum Subarray V | Hard | |
| 622 | Frog Jump | Hard | |
| 623 | K Edit Distance | Hard | |
| 624 | Remove Substrings | Medium | |
| 625 | Partition Array II | Medium | |
| 626 | Rectangle Overlap | Easy | |
| 627 | Longest Palindrome | JavaScript | Easy |
| 628 | Maximum Subtree | Easy | |
| 629 | Minimum Spanning Tree | Hard | |
| 630 | Knight Shortest Path II | Medium | |
| 631 | Maximal Square II | Medium | |
| 632 | Binary Tree Maximum Node | Python | Naive |
| 633 | Find the Duplicate Number | JavaScript | Hard |
| 634 | Word Squares | Hard | |
| 635 | Boggle Game | Hard | |
| 636 | 132 Pattern | Medium | |
| 637 | Valid Word Abbreviation | JavaScript | Easy |
| 638 | Isomorphic Strings | JavaScript | Easy |
| 639 | Word Abbreviation | Hard | |
| 640 | One Edit Distance | Medium | |
| 641 | Missing Ranges | Medium | |
| 642 | Moving Average from Data Stream | Python | Easy |
| 643 | Longest Absolute File Path | Medium | |
| 644 | Strobogrammatic Number | JavaScript | Easy |
| 645 | Find the Celebrity | Medium | |
| 646 | First Position Unique Character | JavaScript | Easy |
| 647 | Find All Anagrams in a String | JavaScript | Easy |
| 648 | Unique Word Abbreviation | Python | Medium |
| 649 | Binary Tree Upside Down | JavaScript | Medium |
| 650 | Find Leaves of Binary Tree | Python | Medium |
| 651 | Binary Tree Vertical Order Traversal | JavaScript | Medium |
| 652 | Factorization | Medium | |
| 653 | Expression Add Operators | Hard | |
| 654 | Sparse Matrix Multiplication | Medium | |
| 655 | Add Strings | JavaScript | Easy |
| 656 | Multiply Strings | Medium | |
| 657 | Insert Delete GetRandom O(1) | Medium | |
| 658 | Swap Without Extra Variable (Only C++) | Easy | |
| 659 | Encode and Decode Strings | Python | Medium |
| 660 | Read N Characters Given Read4 II - Call multiple times | Hard | |
| 661 | Convert BST to Greater Tree | JavaScript | Easy |
| 662 | Guess Number Higher or Lower | Python | Easy |
| 663 | Walls and Gates | Medium | |
| 664 | Counting Bits | JavaScript | Medium |
| 665 | Range Sum Query 2D - Immutable | Python | Medium |
| 666 | Guess Number Higher or Lower II | Medium | |
| 667 | Longest Palindromic Subsequence | Medium | |
| 668 | Ones and Zeroes | Medium | |
| 669 | Coin Change | JavaScript | Medium |
| 670 | Predict the Winner | JavaScript | Medium |
| 671 | Rotate Words | Python | Easy |
| 676 | Decode Ways II | Hard | |
| 677 | Number of Big Islands | Medium | |
| 678 | Shortest Palindrome | Medium | |
| 679 | Unique Paths III | Hard | |
| 680 | Split String | Python | Medium |
| 681 | First Missing Prime Number | Medium | |
| 683 | Word Break III | Medium | |
| 684 | Missing String | JavaScript | Easy |
| 685 | First Unique Number in Data Stream | JavaScript | Medium |
| 686 | Remove Arbitrary Space | JavaScript | Easy |
| 688 | The Number In Words | Medium | |
| 689 | Two Sum IV - Input is a BST | Python | Medium |
| 690 | Factorial | Hard | |
| 691 | Recover Binary Search Tree | JavaScript | Medium |
| 692 | Sliding Window Unique Elements Sum | JavaScript | Medium |
| 693 | Remove Dights | Easy | |
| 696 | Course Schedule III | Hard | |
| 697 | Sum of Square Numbers | JavaScript | Easy |
| 698 | Maximum Distance in Arrays | Medium | |
| 699 | Check Sum of K Primes | Hard | |
| 700 | Cutting a Rod | JavaScript | Medium |
| 701 | Trim a Binary Search Tree | JavaScript | Medium |
| 702 | Concatenated String with Uncommon Characters of Two Strings | JavaScript | Easy |
| 703 | Folding Array | Hard | |
| 704 | Bulb Switcher II | Medium | |
| 706 | Binary Watch | Medium | |
| 707 | Optimal Account Balancing | Super | |
| 708 | Elevator system - OO Design | Hard | |
| 709 | Restaurant OO Design | Hard | |
| 710 | Hotel OO Design | Hard | |
| 712 | Vending machine OO Design | Hard | |
| 714 | Black Jack OO Design | Medium | |
| 716 | Add and Search | Easy | |
| 717 | Tree Longest Path With Same Value | Medium | |
| 718 | Repeat String | Medium | |
| 719 | Calculate Maximum Value | Medium | |
| 720 | Rearrange a String With Integers | JavaScript | Easy |
| 721 | Next Sparse Number | Hard | |
| 722 | Maximum Subarray VI | Super | |
| 723 | Rotate Bits - Left | Medium | |
| 724 | Minimum Partition | Medium | |
| 725 | Boolean Parenthesization | Hard | |
| 726 | Check Full Binary Tree | JavaScript | Medium |
| 727 | Chinese Remainder Theorem | Hard | |
| 728 | Three Distinct Factors | Medium | |
| 729 | Last Digit By Factorial Divide | Medium | |
| 730 | Sum of All Subsets | JavaScript | Easy |
| 731 | Restaurant II OO Design | Hard | |
| 732 | Hotel II OO Design | Hard | |
| 734 | Number of Subsequences of Form a^i b^j c^k | Medium | |
| 735 | Replace With Greatest From Right | Python | Medium |
| 737 | Find Elements in Matrix | JavaScript | Easy |
| 738 | Count Different Palindromic Subsequences | Hard | |
| 739 | 24 Game | Hard | |
| 740 | Coin Change 2 | JavaScript | Medium |
| 741 | Calculate Maximum Value II | Medium | |
| 742 | Self Dividing Numbers | Medium | |
| 743 | Monotone Increasing Digits | Medium | |
| 744 | Sum of first K even-length Palindrome numbers | Medium | |
| 745 | Palindromic Ranges | Medium | |
| 746 | Design Tic-Tac-Toe | Hard | |
| 747 | Coffee Maker OO Design | Medium | |
| 748 | Kindle OO Design | Medium | |
| 749 | John's backyard garden | JavaScript | Easy |
| 750 | Portal | Medium | |
| 751 | John's business | Medium | |
| 752 | Rogue Knight Sven | Medium | |
| 756 | Multiply Two Numbers | JavaScript | Easy |
| 757 | Shortest Unordered Array | Easy | |
| 759 | Time Angle | JavaScript | Easy |
| 760 | Binary Tree Right Side View | JavaScript | Medium |
| 761 | Smallest Subset | JavaScript | Medium |
| 762 | Longest Common Subsequence II | Hard | |
| 763 | Hex Conversion | JavaScript | Easy |
| 764 | Calculate Circumference And Area | Python | Easy |
| 765 | Valid Triangle | JavaScript | Easy |
| 766 | Leap Year | JavaScript | Easy |
| 767 | Reverse Array | JavaScript | Easy |
| 768 | Yang Hui Triangle | JavaScript | Easy |
| 769 | Spiral Array | JavaScript | Easy |
| 770 | Maximum and Minimum | JavaScript | Easy |
| 771 | Double Factorial | Easy | |
| 772 | Group Anagrams | Medium | |
| 773 | Vlid Anagram | JavaScript | Easy |
| 774 | Repeated DNA | JavaScript | Medium |
| 775 | Palindrome Pairs | Hard | |
| 776 | Strobogrammatic Number II | Medium | |
| 777 | Valid Perfect Square | JavaScript | Easy |
| 778 | Pacific Atlantic Water Flow | Python | Medium |
| 779 | Generalized Abbreviation | Medium | |
| 780 | Remove Invalid Parentheses | Hard | |
| 782 | AND and OR | Medium | |
| 783 | Minimum Risk Path | Hard | |
| 784 | The Longest Common Prefix II | Easy | |
| 785 | Maximum Weighted Sum Path | JavaScript | Medium |
| 786 | Linked List Weighted Sum In Reverse Order | Easy | |
| 787 | The Maze | Medium | |
| 788 | The Maze II | Medium | |
| 789 | The Maze III | Hard | |
| 790 | Parser | Medium | |
| 791 | Merge Number | JavaScript | Medium |
| 792 | Kth Prime Number | Easy | |
| 793 | Intersection of Arrays | Medium | |
| 794 | Sliding Puzzle II | Hard | |
| 795 | 4-Way Unique Paths | Hard | |
| 796 | Open the Lock | Hard | |
| 797 | Reach a Number | Easy | |
| 798 | Backpack VII | Medium | |
| 799 | Backpack VIII | Medium | |
| 800 | Backpack IX | JavaScript | Medium |
| 801 | Backpack X | Medium | |
| 802 | Sudoku Solver | Hard | |
| 803 | Shortest Distance from All Buildings | Hard | |
| 804 | Number of Distinct Islands II | Hard | |
| 805 | Maximum Association Set | Medium | |
| 806 | Buy Fruits | Medium | |
| 807 | Palindrome Number II | Easy | |
| 808 | Movie Network | Medium | |
| 809 | K-th Symbol in Grammar | Medium | |
| 810 | Swim in Rising Water | Hard | |
| 811 | Swap Adjacent in LR String | Medium | |
| 812 | Bold Words in String | Easy | |
| 813 | Find Anagram Mappings | JavaScript | Easy |
| 814 | Shortest Path in Undirected Graph | Medium | |
| 815 | Course Schedule IV | Hard | |
| 816 | Traveling Salesman Problem | Hard | |
| 817 | Range Sum Query 2D - Mutable | Medium | |
| 818 | Subset With Target | Hard | |
| 819 | Word Sorting | Medium | |
| 820 | Rectangle | Medium | |
| 821 | Time Intersection | Medium | |
| 822 | Reverse Order Storage | JavaScript | Easy |
| 823 | Input Stream | JavaScript | Easy |
| 824 | Single Number IV | JavaScript | Medium |
| 825 | Bus Station | Hard | |
| 826 | Computer Maintenance | Hard | |
| 828 | Word Pattern | JavaScript | Easy |
| 829 | Word Pattern II | Hard | |
| 830 | String Sort | Easy | |
| 831 | 3Sum II | Medium | |
| 832 | Count Negative Number | Medium | |
| 833 | Process Sequence | Medium | |
| 834 | Remove Duplicate Letters | JavaScript | Easy |
| 835 | Hamming Distance | JavaScript | Easy |
| 836 | Partition to K Equal Sum Subsets | Hard | |
| 837 | Palindromic Substrings | JavaScript | Easy |
| 838 | Subarray Sum Equals K | JavaScript | Easy |
| 839 | Merge Two Sorted Interval Lists | Easy | |
| 840 | Range Sum Query - Mutable | Python | Medium |
| 841 | String Replace | Hard | |
| 842 | Origami | Medium | |
| 843 | Digital Flip | JavaScript | Medium |
| 844 | Number Pair Statistics | Easy | |
| 845 | Greatest Common Divisor | JavaScript | Easy |
| 846 | Multi-keyword Sort | JavaScript | Easy |
| 848 | Minimize Max Distance to Gas Station | Hard | |
| 849 | Basic Calculator III | Hard | |
| 850 | Employee Free Time | Hard | |
| 851 | Pour Water | Medium | |
| 852 | IP to CIDR | Easy | |
| 853 | Number Of Corner Rectangles | Medium | |
| 854 | Closest Leaf in a Binary Tree | JavaScript | Medium |
| 855 | Sentence Similarity II | Medium | |
| 856 | Sentence Similarity | JavaScript | Easy |
| 857 | Minimum Window Subsequence | Hard | |
| 858 | Candy Crush | Medium | |
| 859 | Max Stack | Python | Hard |
| 860 | Number of Distinct Islands | Medium | |
| 861 | K Empty Slots | Hard | |
| 862 | Next Closest Time | Medium | |
| 863 | Binary Tree Path Sum IV | Medium | |
| 864 | Equal Tree Partition | JavaScript | Medium |
| 865 | Remove 9 | Hard | |
| 866 | Coin Path | Hard | |
| 867 | 4 Keys Keyboard | Medium | |
| 868 | Maximum Average Subarray | JavaScript | Easy |
| 869 | Find the Derangement of An Array | Medium | |
| 871 | Minimum Factorization | Medium | |
| 872 | Kill Process | Python | Easy |
| 873 | Squirrel Simulation | Medium | |
| 874 | Maximum Vacation Days | Hard | |
| 875 | Longest Line of Consecutive One in Matrix | JavaScript | Medium |
| 876 | Split Concatenated Strings | Medium | |
| 877 | Split Array with Equal Sum | Medium | |
| 878 | Boundary of Binary Tree | Medium | |
| 879 | Output Contest Matches | Medium | |
| 880 | Construct Binary Tree from String | JavaScript | Medium |
| 881 | Lonely Pixel II | Medium | |
| 883 | Max Consecutive Ones II | JavaScript | Medium |
| 884 | Find Permutation | Medium | |
| 885 | Encode String with Shortest Length | Hard | |
| 886 | Convex Polygon | Medium | |
| 887 | Ternary Expression Parser | Medium | |
| 888 | Valid Word Square | JavaScript | Easy |
| 889 | Sentence Screen Fitting | Medium | |
| 890 | Minimum Unique Word Abbreviation | Hard | |
| 891 | Valid Palindrome II | JavaScript | Medium |
| 892 | Alien Dictionary | Hard | |
| 893 | Longest Palindromic Substring II | Hard | |
| 894 | Pancake Sorting | Medium | |
| 895 | Friend Request | Easy | |
| 896 | Prime Product | Medium | |
| 897 | Island City | Easy | |
| 898 | Leftmost One | Medium | |
| 900 | Closest Binary Search Tree Value | JavaScript | Easy |
| 901 | Closest Binary Search Tree Value II | Hard | |
| 902 | Kth Smallest Element in a BST | JavaScript | Medium |
| 903 | Range Addition | Medium | |
| 904 | Plus One Linked List | JavaScript | Medium |
| 905 | Nested List Weight Sum II | Medium | |
| 906 | Sort Transformed Array | JavaScript | Medium |
| 908 | Line Reflection | JavaScript | Medium |
| 909 | Android Unlock Patterns | Medium | |
| 910 | Largest BST Subtree | Medium | |
| 911 | Maximum Size Subarray Sum Equals k | JavaScript | Medium |
| 912 | Best Meeting Point | Hard | |
| 913 | Flip Game II | Medium | |
| 914 | Flip Game | JavaScript | Easy |
| 915 | Inorder Predecessor in BST | Medium | |
| 916 | Palindrome Permutation | JavaScript | Easy |
| 917 | Palindrome Permutation II | Medium | |
| 918 | 3Sum Smaller | JavaScript | Medium |
| 919 | Meeting Rooms II | Medium | |
| 920 | Meeting Rooms | JavaScript | Easy |
| 921 | Count Univalue Subtrees | Medium | |
| 922 | Group Shifted Strings | Medium | |
| 923 | Strobogrammatic Number III | Hard | |
| 924 | Shortest Word Distance | JavaScript | Easy |
| 926 | Shortest Word Distance III | Medium | |
| 927 | Reverse Words in a String II | JavaScript | Medium |
| 928 | Longest Substring with At Most Two Distinct Characters | Hard | |
| 930 | Connected Components in List | Medium | |
| 931 | Median of K Sorted Arrays | Hard | |
| 932 | Friends Within Three Jumps | Medium | |
| 933 | Tuple Multiply | Medium | |
| 934 | Unlock Problem | Medium | |
| 935 | Cartesian Product | Medium | |
| 936 | Capitalizes The First Letter | JavaScript | Easy |
| 937 | How Many Problem Can I Accept | Medium | |
| 939 | Binary Tree Kth Floor Node | Medium | |
| 940 | Maximum Absolute Value | Medium | |
| 941 | Sliding Puzzle | Hard | |
| 943 | Range Sum Query - Immutable | Python | Easy |
| 944 | Maximum Submatrix | Medium | |
| 945 | Task Scheduler | Medium | |
| 946 | 233 Matrix | Medium | |
| 947 | Matrix Power Series | Hard | |
| 948 | Sequence Count | Super | |
| 949 | Fibonacci II | Medium | |
| 950 | Sliding Puzzle III | Hard | |
| 951 | Rearrange | Easy | |
| 952 | Digital Problem | Easy | |
| 953 | The Biggest Score On The Tree | Medium | |
| 954 | Insert Delete GetRandom O(1) - Duplicates allowed | Hard | |
| 955 | Implement Queue by Circular Array | Python | Medium |
| 956 | Data Segmentation | Easy | |
| 957 | Radar Detection | Easy | |
| 958 | Palindrome Data Stream | Easy | |
| 959 | K Spaced Array Sorting | Medium | |
| 960 | First Unique Number in Data Stream II | Python | Medium |
| 962 | Condition string | Medium | |
| 963 | The Judges Give Problem | Medium | |
| 964 | Food Set | Hard | |
| 965 | LR String | Medium | |
| 966 | Closest Pair of Points | Hard | |
| 967 | Quality Inspection | Hard | |
| 968 | Valid Currency Amount | Medium | |
| 969 | Longest Repeating Substring | Medium | |
| 970 | Big Business | Easy | |
| 971 | Surplus Value Backpack | Hard | |
| 972 | Deliver The Message | Medium | |
| 973 | 1-bit and 2-bit Characters | JavaScript | Easy |
| 974 | 01 Matrix | JavaScript | Medium |
| 975 | 2 Keys Keyboard | Medium | |
| 976 | 4Sum II | JavaScript | Medium |
| 977 | Base 7 | JavaScript | Easy |
| 978 | Basic Calculator | Medium | |
| 979 | Additive Number | Medium | |
| 980 | Basic Calculator II | Medium | |
| 981 | Basic Calculator IV | Hard | |
| 982 | Arithmetic Slices | JavaScript | Medium |
| 983 | Baseball Game | JavaScript | Easy |
| 984 | Arithmetic Slices II - Subsequence | Hard | |
| 985 | Can I Win | Hard | |
| 986 | Battleships in a Board | Python | Medium |
| 987 | Binary Number with Alternating Bits | JavaScript | Easy |
| 988 | Arranging Coins | JavaScript | Easy |
| 989 | Array Nesting | Medium | |
| 990 | Beautiful Arrangement | Medium | |
| 991 | Bulb Switcher | Medium | |
| 992 | Beautiful Arrangement II | Medium | |
| 993 | Array Partition I | JavaScript | Easy |
| 994 | Contiguous Array | JavaScript | Medium |
| 995 | Best Time to Buy and Sell Stock with Cooldown | JavaScript | Medium |
| 996 | Maximum Slope Straight Line | Medium | |
| 997 | Print Organization Chart | Medium | |
| 998 | Construction Queue | Hard | |
| 999 | implement-deque-by-circular-array | Medium | |
| 1000 | Best Time to Buy and Sell Stock with Transaction Fee | JavaScript | Medium |
| 1001 | Asteroid Collision | JavaScript | Medium |
| 1002 | Bus Routes | Medium | |
| 1003 | Binary Tree Pruning | JavaScript | Easy |
| 1004 | Largest Sum of Averages | JavaScript | Medium |
| 1005 | Largest Triangle Area | JavaScript | Easy |
| 1006 | Subdomain Visit Count | JavaScript | Easy |
| 1007 | Chalkboard XOR Game | Medium | |
| 1008 | Expressive Words | Medium | |
| 1010 | Max Increase to Keep City Skyline | JavaScript | Medium |
| 1011 | Number of Lines To Write String | JavaScript | Easy |
| 1012 | Split Array With Same Average | Hard | |
| 1013 | Unique Morse Code Words | JavaScript | Easy |
| 1014 | Bricks Falling When Hit | Hard | |
| 1015 | Find Eventual Safe States | Medium | |
| 1016 | Minimum Swaps To Make Sequences Increasing | Medium | |
| 1017 | Similar RGB Color | Easy | |
| 1018 | Champagne Tower | JavaScript | Medium |
| 1019 | Smallest Rotation with Highest Score | Hard | |
| 1020 | All Paths From Source to Target | Medium | |
| 1021 | Number of Subarrays with Bounded Maximum | Medium | |
| 1022 | Valid Tic-Tac-Toe State | JavaScript | Medium |
| 1023 | Preimage Size of Factorial Zeroes Function | Hard | |
| 1024 | Number of Matching Subsequences | Medium | |
| 1025 | Custom Sort String | Medium | |
| 1026 | Domino and Tromino Tiling | Medium | |
| 1027 | Escape The Ghosts | JavaScript | Medium |
| 1028 | Rotated Digits | Easy | |
| 1029 | Cheapest Flights Within K Stops | Medium | |
| 1030 | K-th Smallest Prime Fraction | Hard | |
| 1031 | Is Graph Bipartite? | Medium | |
| 1032 | Letter Case Permutation | JavaScript | Easy |
| 1033 | Minimum Difference Between BST Nodes | JavaScript | Easy |
| 1034 | Transform to Chessboard | Hard | |
| 1035 | Rabbits in Forest | JavaScript | Medium |
| 1036 | Reach Points | Hard | |
| 1037 | Global and Local Inversions | Medium | |
| 1038 | Jewels And Stones | JavaScript | Easy |
| 1039 | Max Chunks To Make Sorted | Medium | |
| 1040 | Max Chunks To Make Sorted II | Hard | |
| 1041 | Reorganize String | Medium | |
| 1042 | Toeplitz Matrix | JavaScript | Easy |
| 1043 | Couples Holding Hands | Hard | |
| 1044 | Largest Plus Sign | Medium | |
| 1045 | Partition Labels | Medium | |
| 1046 | Prime Number of Set Bits in Binary Representation | Easy | |
| 1047 | Special Binary String | Medium | |
| 1048 | Set Intersection Size At Least Two | Hard | |
| 1049 | Pyramid Transition Matrix | Medium | |
| 1050 | Cracking the Safe | Hard | |
| 1051 | Contain Virus | Hard | |
| 1052 | Shortest Completing Word | Medium | |
| 1053 | Largest Number At Least Twice of Others | JavaScript | Easy |
| 1054 | Min Cost Climbing Stairs | JavaScript | Easy |
| 1056 | Find Smallest Letter Greater Than Target | JavaScript | Easy |
| 1057 | Network Delay Time | Medium | |
| 1058 | Cherry Pickup | Hard | |
| 1059 | Delete and Earn | JavaScript | Medium |
| 1060 | Daily Temperatures | Python | Medium |
| 1061 | Parse Lisp Expression | Hard | |
| 1062 | Flood Fill | JavaScript | Easy |
| 1063 | My Calendar III | Hard | |
| 1064 | My Calendar II | Medium | |
| 1065 | My Calendar I | Medium | |
| 1066 | Verify Preorder Serialization of a Binary Tree | JavaScript | Medium |
| 1067 | Split Linked List in Parts | Medium | |
| 1068 | Find Pivot Index | JavaScript | Easy |
| 1069 | Remove Comments | Medium | |
| 1070 | Accounts Merge | Medium | |
| 1071 | Longest Word in Dictionary | Easy | |
| 1072 | Find K-th Smallest Pair Distance | Hard | |
| 1073 | Maximum Length of Repeated Subarray | Medium | |
| 1074 | Range Module | Hard | |
| 1075 | Subarray Product Less Than K | Medium | |
| 1076 | Minimum ASCII Delete Sum for Two Strings | JavaScript | Medium |
| 1077 | Falling Squares | Hard | |
| 1078 | Degree of an Array | Easy | |
| 1079 | Count Binary Substrings | Easy | |
| 1080 | Max Area of Island | JavaScript | Easy |
| 1081 | Stickers to Spell Word | Hard | |
| 1082 | Employee Importance | Python | Easy |
| 1083 | Maximum Sum of 3 Non-Overlapping Subarrays | Hard | |
| 1084 | Knight Probability in Chessboard | Medium | |
| 1085 | Longest Univalue Path | JavaScript | Easy |
| 1086 | Repeated String Match | Easy | |
| 1087 | Redundant Connection II | Hard | |
| 1088 | Redundant Connection | Medium | |
| 1089 | Valid Parenthesis String | JavaScript | Medium |
| 1090 | Map Sum Pairs | Medium | |
| 1092 | Cut Off Trees for Golf Event | Hard | |
| 1093 | Number of Longest Increasing Subsequence | JavaScript | Medium |
| 1094 | Second Minimum Node In a Binary Tree | JavaScript | Easy |
| 1095 | Maximum Swap | JavaScript | Medium |
| 1096 | Greatest common multiple | Medium | |
| 1097 | Kth Smallest Number in Multiplication Table | Hard | |
| 1098 | Path Sum IV | Medium | |
| 1099 | Non-decreasing Array | JavaScript | Easy |
| 1100 | Strange Printer | Hard | |
| 1101 | Maximum Width of Binary Tree | JavaScript | Medium |
| 1102 | Image Smoother | Easy | |
| 1103 | Split Array into Consecutive Subsequences | Medium | |
| 1104 | Judge Route Circle | Easy | |
| 1105 | Print Binary Tree | JavaScript | Medium |
| 1106 | Maximum Binary Tree | JavaScript | Easy |
| 1108 | Find Duplicate Subtrees | Medium | |
| 1109 | Dota2 Senate | Medium | |
| 1110 | Replace Words | Medium | |
| 1111 | Maximum Length of Pair Chain | Medium | |
| 1112 | Set Mismatch | JavaScript | Easy |
| 1113 | Solve the Equation | Medium | |
| 1114 | Shopping Offers | Medium | |
| 1115 | Average of Levels in Binary Tree | JavaScript | Easy |
| 1116 | Exclusive Time of Functions | Medium | |
| 1117 | Smallest Range | Hard | |
| 1118 | K Inverse Pairs Array | Hard | |
| 1119 | Maximum Product of Three Numbers | JavaScript | Easy |
| 1122 | Add One Row to Tree | JavaScript | Medium |
| 1125 | Jump Pillar | Medium | |
| 1126 | Merge Two Binary Trees | JavaScript | Easy |
| 1127 | Add Bold Tag in String | Medium | |
| 1129 | Smallest Subtree with All the Deepest Nodes | Medium | |
| 1130 | Magic circle | Hard | |
| 1131 | The Function in Permutations | Medium | |
| 1132 | Valid Triangle Number | Medium | |
| 1133 | Group Buy | Easy | |
| 1134 | Find Duplicate File in System | Medium | |
| 1135 | Feature extraction | Easy | |
| 1136 | High Click Induction Area | Medium | |
| 1137 | Construct String from Binary Tree | JavaScript | Easy |
| 1138 | Can Place Flowers | JavaScript | Easy |
| 1139 | the kth subarray | Hard | |
| 1141 | The month's days | Easy | |
| 1142 | Non-negative Integers without Consecutive Ones | Hard | |
| 1143 | Minimum Index Sum of Two Lists | JavaScript | Easy |
| 1144 | Range Addition II | Easy | |
| 1145 | Associated query | Easy | |
| 1146 | Chess piece rotation | Easy | |
| 1147 | Work Plan | Medium | |
| 1148 | Longest Harmonious Subsequence | Easy | |
| 1149 | Valid Square | JavaScript | Medium |
| 1150 | Fraction Addition and Subtraction | Medium | |
| 1151 | Tag Validator | Hard | |
| 1152 | Erect the Fence | Hard | |
| 1153 | string sorting | Easy | |
| 1154 | Attendance Judgment | Easy | |
| 1156 | Delete Operation for Two Strings | JavaScript | Medium |
| 1157 | Shortest Unsorted Continuous Subarray | Easy | |
| 1158 | Plant flowers | Medium | |
| 1159 | Longest Common Prefix III | Hard | |
| 1160 | Campus Bikes | Medium | |
| 1161 | goods transfer | Hard | |
| 1162 | Out of Boundary Paths | Medium | |
| 1163 | Distribute Candies | JavaScript | Easy |
| 1164 | Wiggle Subsequence | Medium | |
| 1165 | Subtree of Another Tree | JavaScript | Easy |
| 1166 | Recommended Results are Scattered | Easy | |
| 1167 | Top three numbers | Medium | |
| 1168 | array score | Easy | |
| 1169 | Permutation in String | JavaScript | Medium |
| 1170 | Reshape the Matrix | JavaScript | Easy |
| 1171 | Find the Closest Palindrome | Hard | |
| 1172 | Binary Tree Tilt | JavaScript | Easy |
| 1173 | Reverse Words in a String III | JavaScript | Easy |
| 1174 | Next Greater Element III | Medium | |
| 1175 | Brick Wall | Medium | |
| 1176 | Optimal Division | Medium | |
| 1177 | Student Attendance Record II | Hard | |
| 1178 | Student Attendance Record I | JavaScript | Easy |
| 1179 | Friend Circles | Medium | |
| 1180 | Remove Boxes | Hard | |
| 1181 | Diameter of Binary Tree | JavaScript | Easy |
| 1182 | Reverse String II | JavaScript | Easy |
| 1183 | Single Element in a Sorted Array | JavaScript | Medium |
| 1184 | Minimum Time Difference | JavaScript | Medium |
| 1185 | Complex Number Multiplication | JavaScript | Medium |
| 1186 | Encode and Decode TinyURL | Python | Medium |
| 1187 | K-diff Pairs in an Array | JavaScript | Easy |
| 1188 | Minimum Absolute Difference in BST | JavaScript | Easy |
| 1189 | Minesweeper | Python | Medium |
| 1190 | Longest Word in Dictionary through Deleting | Medium | |
| 1191 | Longest Uncommon Subsequence II | Medium | |
| 1192 | Longest Uncommon Subsequence I | Easy | |
| 1193 | Detect Capital | JavaScript | Easy |
| 1194 | Super Washing Machines | Hard | |
| 1195 | Find Largest Value in Each Tree Row | JavaScript | Medium |
| 1196 | Freedom Trail | Hard | |
| 1197 | Find Bottom Left Tree Value | JavaScript | Medium |
| 1198 | Most Frequent Subtree Sum | Medium | |
| 1199 | Perfect Number | Easy | |
| 1200 | Relative Ranks | JavaScript | Easy |
| 1201 | Next Greater Element II | Medium | |
| 1202 | IPO | Hard | |
| 1203 | Find Mode in Binary Search Tree | JavaScript | Medium |
| 1204 | Keyboard Row | JavaScript | Easy |
| 1205 | Diagonal Traverse | JavaScript | Medium |
| 1206 | Next Greater Element I | Easy | |
| 1207 | Teemo Attacking | Medium | |
| 1208 | Target Sum | JavaScript | Medium |
| 1209 | Construct the Rectangle | JavaScript | Easy |
| 1210 | Increasing Subsequences | Medium | |
| 1211 | Zuma Game | Hard | |
| 1212 | Max Consecutive Ones | JavaScript | Easy |
| 1213 | Smallest Good Base | Hard | |
| 1214 | License Key Formatting | JavaScript | Easy |
| 1215 | Magical String | Medium | |
| 1216 | Largest Palindrome Product | Easy | |
| 1217 | Total Hamming Distance | Medium | |
| 1218 | Number Complement | JavaScript | Easy |
| 1219 | Heaters | Medium | |
| 1220 | Matchsticks to Square | Medium | |
| 1221 | Concatenated Words | Hard | |
| 1222 | Validate IP Address | Medium | |
| 1223 | Unique Substrings in Wraparound String | Medium | |
| 1224 | Count The Repetitions | Hard | |
| 1225 | Island Perimeter | Easy | |
| 1226 | Minimum Moves to Equal Array Elements II | Medium | |
| 1227 | Repeated Substring Pattern | JavaScript | Easy |
| 1228 | Poor Pigs | Easy | |
| 1229 | Circular Array Loop | Medium | |
| 1230 | Assign Cookies | JavaScript | Easy |
| 1231 | Minimum Moves to Equal Array Elements | Easy | |
| 1232 | Minimum Number of Arrows to Burst Balloons | Medium | |
| 1233 | Sort Characters By Frequency | Medium | |
| 1234 | Delete Node in a BST | Medium | |
| 1235 | Serialize and Deserialize BST | Python | Medium |
| 1236 | Find All Numbers Disappeared in an Array | JavaScript | Easy |
| 1237 | Number of Boomerangs | JavaScript | Easy |
| 1238 | Find All Duplicates in an Array | Python | Medium |
| 1239 | K-th Smallest in Lexicographical Order | Hard | |
| 1240 | Path Sum III | Easy | |
| 1241 | Find Right Interval | Medium | |
| 1242 | Non-overlapping Intervals | Medium | |
| 1243 | Number of Segments in a String | JavaScript | Easy |
| 1244 | Minimum Genetic Mutation | Medium | |
| 1245 | All O`one Data Structure | Hard | |
| 1246 | Longest Repeating Character Replacement | Medium | |
| 1247 | Reconstruct Original Digits from English | Medium | |
| 1248 | Maximum XOR of Two Numbers in an Array | Medium | |
| 1249 | Strong Password Checker | Hard | |
| 1250 | Third Maximum Number | JavaScript | Easy |
| 1251 | Split Array Largest Sum | JavaScript | Hard |
| 1252 | Queue Reconstruction by Height | Medium | |
| 1253 | Convert a Number to Hexadecimal | JavaScript | Easy |
| 1254 | Sum of Left Leaves | JavaScript | Easy |
| 1255 | Remove K Digits | Medium | |
| 1256 | Nth Digit | Easy | |
| 1257 | Evaluate Division | Medium | |
| 1258 | Beautiful Subarrays | Medium | |
| 1259 | Integer Replacement | Medium | |
| 1260 | Rotate Function | Medium | |
| 1261 | Longest Substring with At Least K Repeating Characters | Medium | |
| 1262 | UTF-8 Validation | Medium | |
| 1263 | Is Subsequence | JavaScript | Medium |
| 1264 | Perfect Rectangle | Hard | |
| 1265 | Elimination Game | Medium | |
| 1266 | Find the Difference | JavaScript | Easy |
| 1267 | Lexicographical Numbers | JavaScript | Medium |
| 1269 | Handkerchief Throwing | Medium | |
| 1270 | Ransom Note | JavaScript | Easy |
| 1271 | Critical Connections in a Network | Hard | |
| 1272 | Kth Smallest Element in a Sorted Matrix | JavaScript | Medium |
| 1273 | Maximum Length of Increasing String | Hard | |
| 1274 | Find K Pairs with Smallest Sums | Medium | |
| 1275 | Super Pow | JavaScript | Medium |
| 1276 | Sum of Two Integers | Easy | |
| 1277 | Water and Jug Problem | Medium | |
| 1278 | Max Sum of Rectangle No Larger Than K | Hard | |
| 1279 | Count Numbers with Unique Digits | Medium | |
| 1280 | Data Stream as Disjoint Intervals | Hard | |
| 1281 | Top K Frequent Elements | Python | Medium |
| 1282 | Reverse Vowels of a String | JavaScript | Easy |
| 1283 | Reverse String | JavaScript | Easy |
| 1284 | Integer Break | JavaScript | Medium |
| 1285 | Power of Four | JavaScript | Easy |
| 1286 | Self Crossing | Hard | |
| 1287 | Increasing Triplet Subsequence | JavaScript | Medium |
| 1288 | Reconstruct Itinerary | Medium | |
| 1289 | Number of Atoms | Hard | |
| 1290 | Patching Array | Hard | |
| 1291 | Sports Meeting | Medium | |
| 1292 | Odd Even Linked List | JavaScript | Medium |
| 1293 | Count of Range Sum | Hard | |
| 1294 | Power of Three | JavaScript | Easy |
| 1295 | Prime Factor Statistics | Easy | |
| 1296 | Maximum Product of Word Lengths | Medium | |
| 1297 | Count of Smaller Numbers After Self | Hard | |
| 1298 | Minimum Height Trees | Medium | |
| 1299 | Bulls and Cows | Medium | |
| 1300 | Bash Game | JavaScript | Easy |
| 1301 | Game of Life | Medium | |
| 1302 | People Counting | Easy | |
| 1303 | H-Index II | Medium | |
| 1304 | H-Index | Medium | |
| 1305 | Integer to English Words | Medium | |
| 1306 | Travel Plan II | Hard | |
| 1307 | Verify Preorder Sequence in Binary Search Tree | JavaScript | Medium |
| 1308 | Factor Combinations | Medium | |
| 1309 | Different Ways to Add Parentheses | Medium | |
| 1310 | Product of Array Except Self | JavaScript | Medium |
| 1311 | Lowest Common Ancestor of a Binary Search Tree | Python | Easy |
| 1312 | Number of Digit One | JavaScript | Hard |
| 1313 | Bipartite Graph | Medium | |
| 1314 | Power of Two | JavaScript | Easy |
| 1315 | Summary Ranges | Medium | |
| 1316 | Luck Number | Hard | |
| 1317 | Count Complete Tree Nodes | JavaScript | Medium |
| 1318 | Contains Duplicate III | Medium | |
| 1319 | Contains Duplicate II | JavaScript | Easy |
| 1320 | Contains Duplicate | JavaScript | Easy |
| 1321 | Combination Sum III | Medium | |
| 1322 | Product Equal B | Hard | |
| 1323 | Fetch supplies | Medium | |
| 1324 | Count Primes | JavaScript | Easy |
| 1325 | Bitwise AND of Numbers Range | Medium | |
| 1326 | Boarder Sort | Medium | |
| 1327 | delete string | Easy | |
| 1328 | Double Change | Easy | |
| 1329 | Sequence maintenance | Hard | |
| 1330 | zero matrix | Hard | |
| 1331 | English Software | Easy | |
| 1332 | Number of 1 Bits | JavaScript | Easy |
| 1333 | Reverse Bits | JavaScript Python | Easy |
| 1334 | Rotate Array | JavaScript | Easy |
| 1335 | Repeated DNA Sequences | JavaScript | Medium |
| 1336 | Invite your friend | Medium | |
| 1337 | Maximum Possible Value | Medium | |
| 1338 | Parking Dilemma | Easy | |
| 1339 | Maximum Range | Hard | |
| 1340 | add character | Easy | |
| 1341 | Combine New Numbers | Medium | |
| 1342 | substitute string | Medium | |
| 1343 | Sum of Two Strings | Python | Easy |
| 1344 | Counter Diagonal Sort | Medium | |
| 1345 | Robot Encircular | Medium | |
| 1346 | Dungeon Game | Hard | |
| 1347 | Factorial Trailing Zeroes | JavaScript | Easy |
| 1348 | Excel Sheet Column Number | JavaScript | Easy |
| 1350 | Excel Sheet Column Title | JavaScript | Easy |
| 1351 | Fraction to Recurring Decimal | Medium | |
| 1352 | Compare Version Numbers | JavaScript | Medium |
| 1353 | Sum Root to Leaf Numbers | JavaScript | Medium |
| 1354 | Pascal's Triangle II | JavaScript | Easy |
| 1355 | Pascal's Triangle | JavaScript | Easy |
| 1356 | Maximum Points Set | Medium | |
| 1357 | Path Sum II | JavaScript | Medium |
| 1358 | Path Sum | JavaScript | Easy |
| 1359 | Convert Sorted Array to Binary Search Tree | JavaScript | Easy |
| 1360 | Symmetric Tree | JavaScript | Medium |
| 1361 | Text Justification | Hard | |
| 1362 | Substring with Concatenation of All Words | Hard | |
| 1363 | ZigZag Conversion | Medium | |
| 1364 | the minium distance | Medium | |
| 1365 | Minimum Cycle Section | Hard | |
| 1366 | Directed Graph Loop | Medium | |
| 1367 | Police Distance | Medium | |
| 1368 | Same Number | JavaScript | Easy |
| 1369 | Most Common Word | Easy | |
| 1370 | Race Car | Hard | |
| 1371 | Linked List Components | JavaScript | Medium |
| 1372 | Ambiguous Coordinates | Medium | |
| 1373 | Movies on Flight | Medium | |
| 1374 | Shortest Distance in 3D Space | Medium | |
| 1375 | Substring With At Least K Distinct Characters | Medium | |
| 1376 | Equivalent Strings | Medium | |
| 1377 | Find Substring | Medium | |
| 1378 | Minimum String Array Coverage | Medium | |
| 1379 | The Longest Scene | Hard | |
| 1380 | Log Sorting | Easy | |
| 1381 | Maximum Line Coverage | Hard | |
| 1382 | High Capacity Backpack | Medium | |
| 1383 | Subtree Count | Hard | |
| 1384 | Segment Stones Merge | Super | |
| 1385 | Lucky Number Eight | Easy | |
| 1386 | Cable Car Ride | Easy | |
| 1387 | Binary Trees With Factors | Medium | |
| 1388 | Card Flipping Game | Medium | |
| 1389 | Shortest Distance to a Character | Easy | |
| 1390 | Short Encoding of Words | Medium | |
| 1391 | Making A Large Island | Hard | |
| 1392 | Most Profit Assigning Work | Medium | |
| 1393 | Friends Of Appropriate Ages | Medium | |
| 1394 | Goat Latin | JavaScript | Easy |
| 1395 | The Barycentre Of The Trees | Hard | |
| 1396 | Set Union | Medium | |
| 1397 | Digital Coverage | Medium | |
| 1398 | K Decimal Addition | Easy | |
| 1399 | Take Coins | Medium | |
| 1400 | Fermat Point Of Graphs | Hard | |
| 1401 | Twitch Words | JavaScript | Easy |
| 1402 | Recommend Friends | Medium | |
| 1403 | Maximum Product Path | Medium | |
| 1408 | Gas Station II | Hard | |
| 1409 | Matrix Finding Number | Medium | |
| 1410 | Matrix Water Injection | Easy | |
| 1411 | Edit Distance - Replace Edition | Medium | |
| 1412 | Pick Three Numbers | Medium | |
| 1413 | Tree | Medium | |
| 1414 | Eat The Beans | Hard | |
| 1415 | Residual Product | Easy | |
| 1416 | The Previous Number | Medium | |
| 1417 | Weighing Problem | Easy | |
| 1418 | Path With Maximum Minimum Value | Medium | |
| 1420 | Minimum Window Substring II | Medium | |
| 1421 | Matrix Game | Easy | |
| 1422 | Shortest Path Visiting All Nodes | Hard | |
| 1423 | Hand of Straights | Medium | |
| 1424 | Longest Mountain in Array | JavaScript | Medium |
| 1425 | Backspace String Compare | JavaScript | Easy |
| 1426 | Robot jumping | Hard | |
| 1427 | Split Array into Fibonacci Sequence | Medium | |
| 1428 | Keys and Rooms | Medium | |
| 1430 | Similar String Groups | Hard | |
| 1431 | Push Dominoes | Medium | |
| 1432 | New 21 Game | Medium | |
| 1433 | Image Overlap | Medium | |
| 1434 | Sum of Distances in Tree | Hard | |
| 1435 | Find And Replace in String | Medium | |
| 1436 | Flipping an Image | Easy | |
| 1437 | Masking Personal Information | Medium | |
| 1438 | Positions of Large Groups | JavaScript | Easy |
| 1439 | Consecutive Numbers Sum | Medium | |
| 1440 | Unique Letter String | Hard | |
| 1441 | Four Numbers Multiply Problem | Hard | |
| 1442 | Order Problem | Medium | |
| 1443 | Longest AB Substring | Easy | |
| 1444 | Dyeing Problem | Medium | |
| 1445 | Delete Characters | Easy | |
| 1446 | 01 Matrix Walking Problem | Medium | |
| 1447 | Calculation The Sum Of Path | Medium | |
| 1448 | Card Game | Medium | |
| 1449 | Loud and Rich | Medium | |
| 1450 | Rectangle Area II | Hard | |
| 1451 | Maximize Distance to Closest Person | JavaScript | Easy |
| 1452 | Shifting Letters | Medium | |
| 1453 | Minimum Amount | Medium | |
| 1454 | Word Frequency Count | Medium | |
| 1455 | Valid Array | Easy | |
| 1456 | Word Synthesis Problem | Hard | |
| 1457 | Search Subarray | Medium | |
| 1458 | Minimum Submatrix | Medium | |
| 1459 | Judge the last number | Easy | |
| 1463 | Paper Review | Medium | |
| 1464 | The K-th Combination | Hard | |
| 1465 | Order Of Tasks | Medium | |
| 1466 | Best Shopping Plan | Medium | |
| 1467 | Ask For Cooling Time | Medium | |
| 1468 | Two Numbers That Are Not Repeated | Hard | |
| 1469 | Longest Path On The Tree | Medium | |
| 1470 | The Game Of Take Numbers | Medium | |
| 1471 | Set Operation | Easy | |
| 1472 | Twins Strings | Easy | |
| 1473 | Find The Sum Of The Array | Medium | |
| 1474 | Shortest Phrase | Medium | |
| 1475 | Minimum Legal Bracket Sequence | Hard | |
| 1476 | Peak Index in a Mountain Array | Easy | |
| 1477 | Car Fleet | JavaScript | Medium |
| 1478 | Closest Target Value | Easy | |
| 1479 | Can Reach The Endpoint | Easy | |
| 1480 | Dot Product | Easy | |
| 1481 | Unique Substring | Medium | |
| 1482 | Minimum Sum Path | Medium | |
| 1483 | Maximum Average Score | JavaScript | Easy |
| 1484 | The Most Frequent word | Medium | |
| 1485 | Holy Grail spell | Python | Easy |
| 1486 | Function Runtime | Easy | |
| 1487 | Judging Triangle | Medium | |
| 1488 | Longest Sequence | Hard | |
| 1489 | The Largest Sum Of The Matrix Boundary Elements | Medium | |
| 1490 | K-Similar Strings | Hard | |
| 1491 | Score of Parentheses | Medium | |
| 1492 | Koko Eating Bananas | JavaScript | Medium |
| 1493 | Walking Robot Simulation | Easy | |
| 1494 | Length of Longest Fibonacci Subsequence | Medium | |
| 1495 | Leaf-Similar Trees | JavaScript | Easy |
| 1496 | Implement Rand10() Using Rand7() | Medium | |
| 1497 | Minimum Number of Refueling Stops | Hard | |
| 1498 | Advantage Shuffle | Medium | |
| 1499 | Reordered Power of 2 | JavaScript | Medium |
| 1500 | Binary Gap | Easy | |
| 1501 | Transpose Matrix | Easy | |
| 1502 | Prime Palindrome | Medium | |
| 1503 | Give change | Easy | |
| 1504 | Shortest Path to Get All Keys | Hard | |
| 1505 | Find the Number | Python | Easy |
| 1506 | All Nodes Distance K in Binary Tree | Python | Medium |
| 1507 | Shortest Subarray with Sum at Least K | Hard | |
| 1508 | Score After Flipping Matrix | JavaScript | Medium |
| 1509 | Lemonade Change | JavaScript | Easy |
| 1510 | Buddy Strings | JavaScript | Easy |
| 1511 | Mirror Reflection | Medium | |
| 1512 | Minimum Cost to Hire K Workers | Hard | |
| 1513 | Exam Room | Medium | |
| 1514 | Robot Room Cleaner | Hard | |
| 1516 | Xor Sum | Super | |
| 1517 | Largest subarray | JavaScript | Easy |
| 1518 | Watering Flowers | Medium | |
| 1519 | Time magic | Python | Easy |
| 1521 | Unique Twitter User Id Set | Easy | |
| 1522 | Search in a Sorted Array of Unknown Size | Medium | |
| 1523 | Partitioning Array | Easy | |
| 1524 | Search in a Binary Search Tree | JavaScript | Easy |
| 1525 | N-ary Tree Postorder Traversal | Python | Easy |
| 1526 | N-ary Tree Preorder Traversal | Python | Easy |
| 1527 | Majsoul on ! | Medium | |
| 1528 | number schemes | Hard | |
| 1529 | Triplet Subarray With Absolute Diff Less Than or Equal to Limit | Hard | |
| 1530 | Encode N-ary Tree to Binary Tree | Hard | |
| 1531 | Automatic Proofreading Program | Medium | |
| 1532 | Serialize and Deserialize N-ary Tree | Hard | |
| 1533 | N-ary Tree Level Order Traversal | Easy | |
| 1534 | Convert Binary Search Tree to Sorted Doubly Linked List | Medium | |
| 1535 | To Lower Case | JavaScript | Easy |
| 1536 | Find First and Last Position of Element in Sorted Array | JavaScript | Medium |
| 1537 | Swap Zero-One | Medium | |
| 1538 | Card Game II | Medium | |
| 1539 | Flipped the Pixel | Medium | |
| 1540 | Can Convert | Easy | |
| 1541 | Put Box | Hard | |
| 1542 | NextTime Norepeat | Medium | |
| 1543 | Unique Path IV | Medium | |
| 1544 | Magic Square | Hard | |
| 1545 | Last Closest Time | Medium | |
| 1546 | Coin Problem | Easy | |
| 1552 | Parking Problem | Medium | |
| 1553 | Climbing Stairs III | Medium | |
| 1554 | LastTime Norepeat | Medium | |
| 1555 | Flower Problem | Hard | |
| 1556 | Guess Game | Hard | |
| 1557 | Array Maximum Value | Hard | |
| 1558 | Interlaced Positive And Negative Numbers | Hard | |
| 1559 | Take the element and query the sum | Easy | |
| 1560 | MinimumString | Medium | |
| 1561 | BST Node Distance | Medium | |
| 1562 | Number of restaurants | Medium | |
| 1563 | Shortest path to the destination | Medium | |
| 1564 | Interval Search | Easy | |
| 1565 | Modern Ludo I | Medium | |
| 1566 | Minimum Difference | Hard | |
| 1567 | Maximum Can Exchanged Subarray | Medium | |
| 1568 | Poison Test | Medium | |
| 1569 | Social Network | Medium | |
| 1570 | Binary Stream | Easy | |
| 1571 | Top K GPA | Medium | |
| 1572 | Asking For The Longest 01 Substring | Medium | |
| 1573 | Legal String | Medium | |
| 1574 | Music Playlist | Hard | |
| 1575 | Spring Tour | Easy | |
| 1576 | Optimal Match | Hard | |
| 1577 | Sum of leaf nodes | Medium | |
| 1578 | Number of A | JavaScript | Easy |
| 1579 | Alphabetic string calculation | Medium | |
| 1580 | Transition String | Medium | |
| 1581 | Longest Subsequence | Medium | |
| 1582 | Minimum Path Sum II | Medium | |
| 1583 | Maximum Number Sum | Medium | |
| 1584 | Number Of Xor Values | Medium | |
| 1585 | Moving Stones | Easy | |
| 1586 | Minimum Number Of Keystrokes | Medium | |
| 1587 | String Segmentation | Medium | |
| 1588 | All Possible Full Binary Trees | Medium | |
| 1589 | Groups of Special-Equivalent Strings | Easy | |
| 1590 | Surface Area of 3D Shapes | Easy | |
| 1591 | Sum of Subsequence Widths | Hard | |
| 1592 | Find and Replace Pattern | Medium | |
| 1593 | Construct Binary Tree from Preorder and Postorder Traversal | JavaScript | Medium |
| 1594 | Fair Candy Swap | JavaScript | Easy |
| 1596 | Possible Bipartition | Medium | |
| 1597 | Spiral Matrix III | Medium | |
| 1598 | Uncommon Words from Two Sentences | JavaScript | Easy |
| 1599 | Projection Area of 3D Shapes | Easy | |
| 1600 | Reachable Nodes In Subdivided Graph | Hard | |
| 1601 | Boats to Save People | JavaScript | Medium |
| 1602 | Decoded String at Index | Medium | |
| 1604 | Maximum Sum of Two Numbers | Medium | |
| 1606 | Strange Sort | Medium | |
| 1607 | Profitable Schemes | Hard | |
| 1608 | Nth Magical Number | Hard | |
| 1609 | Middle of the Linked List | JavaScript | Easy |
| 1610 | Find the numbers | Medium | |
| 1611 | Shortest subarray | Medium | |
| 1612 | Smallest Path | Medium | |
| 1613 | Highest frequency IP | Naive | |
| 1614 | Highest growth stock | Easy | |
| 1615 | The result of investment | Easy | |
| 1616 | Shortest subarray II | Hard | |
| 1617 | Array Maximum Difference | Easy | |
| 1618 | Processing Form | Medium | |
| 1619 | Candy II | Medium | |
| 1620 | Collecting Coins | Super | |
| 1621 | Cut Connection | Easy | |
| 1623 | Minimal Distance In The Array | Easy | |
| 1624 | Max Distance | Hard | |
| 1625 | Words Compression | Hard | |
| 1626 | Salary Adjustment | Medium | |
| 1627 | Word Segmentation | Medium | |
| 1628 | Driving problem | Medium | |
| 1629 | Find the nearest store | Medium | |
| 1630 | Interesting String | Medium | |
| 1631 | Interesting Subarray | Medium | |
| 1632 | Count email groups | Easy | |
| 1633 | Strings That Satisfies The Condition | Easy | |
| 1634 | Secret Word | Medium | |
| 1635 | Max Pair | Medium | |
| 1636 | Aerial Movie | Medium | |
| 1637 | Tree problem | Medium | |
| 1638 | Least Substring | Easy | |
| 1639 | K-Substring with K different characters | Medium | |
| 1640 | Duplicates Digits | Hard | |
| 1641 | Max Remove Order | Medium | |
| 1642 | Query String | Medium | |
| 1643 | Pick Fruits | Medium | |
| 1644 | Plane Maximum Rectangle | Medium | |
| 1645 | Least Subsequences | Easy | |
| 1646 | CheckWords | Medium | |
| 1647 | Path Search | Medium | |
| 1648 | max substring | Hard | |
| 1649 | Super Lollipop | Easy | |
| 1656 | Legal Number Statistics | JavaScript | Easy |
| 1657 | Operation Time | Easy | |
| 1659 | Legal Number Statistics II | Easy | |
| 1665 | Calculate number | JavaScript | Easy |
| 1669 | Build a temple | Medium | |
| 1685 | The mazeIV | Medium | |
| 1691 | Best Time to Buy and Sell Stock V | Medium | |
| 1694 | Monster Hunter | Hard | |
| 1698 | Delete Columns to Make Sorted | Easy | |
| 1699 | Find the Shortest Superstring | Hard | |
| 1700 | DI String Match | Easy | |
| 1701 | Valid Mountain Array | Easy | |
| 1702 | Distinct Subsequences II | JavaScript | Hard |
| 1703 | Minimum Area Rectangle | Medium | |
| 1704 | Range Sum of BST | JavaScript | Medium |
| 1705 | Compare Strings II | Easy | |
| 1706 | Stamping The Sequence | Hard | |
| 1707 | Knight Dialer | Medium | |
| 1708 | Shortest Bridge | Medium | |
| 1709 | Number of Recent Calls | Easy | |
| 1710 | Beautiful Array | Medium | |
| 1711 | Minimum Falling Path Sum | JavaScript | Medium |
| 1712 | Binary Subarrays With Sum | Medium | |
| 1713 | Unique Email Addresses | Easy | |
| 1714 | Minimize Malware Spread II | Hard | |
| 1715 | Three Equal Parts | Hard | |
| 1716 | Flip String to Monotone Increasing | JavaScript | Medium |
| 1718 | Minimize Malware Spread | Hard | |
| 1719 | 3Sum With Multiplicity | JavaScript | Medium |
| 1721 | Minimum Add to Make Parentheses Valid | JavaScript | Medium |
| 1722 | Number of Music Playlists | Hard | |
| 1723 | Shortest Path in a Grid with Obstacles Elimination | Medium | |
| 1724 | Maximum Sum Circular Subarray | JavaScript | Medium |
| 1725 | Reverse Only Letters | Easy | |
| 1726 | Word Subsets | Medium | |
| 1727 | Partition Array into Disjoint Intervals | JavaScript | Medium |
| 1728 | X of a Kind in a Deck of Cards | Python | Easy |
| 1729 | Cat and Mouse | Hard | |
| 1730 | Spreadsheet Notation Conversion | Easy | |
| 1731 | Smallest Range II | Medium | |
| 1732 | Snakes and Ladders | Medium | |
| 1733 | Smallest Range I | Easy | |
| 1734 | Sum of Subarray Minimums | Medium | |
| 1735 | Super Palindromes | Hard | |
| 1736 | Throw garbage | Medium | |
| 1737 | Fruit Into Baskets | Medium | |
| 1738 | Valid Permutations for DI Sequence | Hard | |
| 1739 | Numbers At Most N Given Digit Set | Medium | |
| 1740 | Online Stock Span | Medium | |
| 1741 | RLE Iterator | Medium | |
| 1742 | Orderly Queue | Hard | |
| 1743 | Bitwise ORs of Subarrays | Medium | |
| 1744 | Increasing Order Search Tree | JavaScript | Easy |
| 1745 | Monotonic Array | JavaScript | Easy |
| 1746 | Minimum Distance Between BST Nodes | JavaScript | Easy |
| 1747 | Robot Return to Origin | Easy | |
| 1753 | Doing Homework | Medium | |
| 1756 | Buy beverage | Medium | |
| 1761 | Digital Huarong Road | Hard | |
| 1767 | Minimum Tree Coverage | Hard | |
| 1772 | Number of collections | Super | |
| 1778 | Odd Even Jump | Hard | |
| 1779 | Shortest Duplicate Subarray | JavaScript | Easy |
| 1780 | The Candidate With the Most Votes | Medium | |
| 1781 | Reverse ASCII Encoded Strings | Easy | |
| 1782 | No Pairs Allowed | Medium | |
| 1783 | Binary Tree Postorder Traversal-null | JavaScript | Easy |
| 1784 | Decrease To Be Palindrome | Easy | |
| 1785 | Bank System | Medium | |
| 1786 | Pub Sub Pattern | Easy | |
| 1787 | Google Suggestion (Map Reduce) | Medium | |
| 1788 | Ascending Binary Sorting | Medium | |
| 1789 | Distinguish Username | Easy | |
| 1790 | Rotate String II | Easy | |
| 1791 | Simple queries | Medium | |
| 1792 | Cut the sticks | Easy | |
| 1793 | Balanced Sales Array | Easy | |
| 1794 | Count Duplicates | Easy | |
| 1795 | Is Possible | Medium | |
| 1796 | K-Difference | Medium | |
| 1797 | optimalUtilization | Easy | |
| 1798 | Minimum Cost to Merge Stones | Hard | |
| 1799 | Sequence summation | Easy | |
| 1800 | Float Combination Sum | Medium | |
| 1801 | the sum of legal set | Easy | |
| 1802 | Grid Game | Medium | |
| 1803 | Rotate beam | Medium | |
| 1804 | Find The Rank | Easy | |
| 1807 | Fibonacci easy | Python | Easy |
| 1808 | Minimum Domino Rotations For Equal Row | Medium | |
| 1809 | Largest Continguous Subarray | Medium | |
| 1811 | Find Maximum Gold | Medium | |
| 1812 | Rotation Number | Easy | |
| 1814 | Sum of all Subarrays | Python | Easy |
| 1815 | Threhold Alerts | Easy | |
| 1816 | Find the Smallest Divisor Given a Threshold | Medium | |
| 1817 | Divide Chocolate | Hard | |
| 1819 | Longest Semi Alternating Substring | Easy | |
| 1820 | Find Letter | Easy | |
| 1821 | Min Deletions To Obtain String in Right Format | Easy | |
| 1822 | Minimum Moves | Easy | |
| 1823 | Longest Prefix of Array | Easy | |
| 1824 | Most Frequent Substring | Medium | |
| 1825 | Number Change | Medium | |
| 1827 | Number of Ways to Stay in the Same Place After Some Steps II | Medium | |
| 1828 | Lake Escape | Hard | |
| 1831 | Array Summarization | Easy | |
| 1832 | Minimum Step | Medium | |
| 1833 | pen box | Medium | |
| 1834 | Grouping Options | Hard | |
| 1835 | Number of Ways to Stay in the Same Place After Some Steps I | Easy | |
| 1836 | Reaching Point | Medium | |
| 1840 | Matrix restoration | Medium | |
| 1844 | subarray sum equals to k II | Medium | |
| 1846 | Reaching Point II | Medium | |
| 1848 | Word Search III | Hard | |
| 1849 | Grumpy Bookstore Owner | Medium | |
| 1850 | Pick Apples | Medium | |
| 1851 | Buy Passes | Medium | |
| 1852 | Final Discounted Price | Medium | |
| 1853 | Efficient Job Processing Service | Medium | |
| 1854 | Partition Array III | Easy | |
| 1855 | Reach Destination | Hard | |
| 1856 | Sub-palindrome | Easy | |
| 1857 | Find Friend Circle Number | Medium | |
| 1858 | Set of boxes | Medium | |
| 1859 | Minimum Amplitude | Easy | |
| 1860 | the Number of 0-submatrix | Medium | |
| 1861 | Rat Jump | Hard | |
| 1862 | Time to Flower Tree | Medium | |
| 1867 | Most Frequent Word II | Easy | |
| 1868 | Find the Number of “Balance” in the String | Medium | |
| 1869 | Count Square Submatrices with All Ones | Medium | |
| 1870 | number of substrings with all zeroes | Medium | |
| 1871 | Maximum moment | Easy | |
| 1872 | Minimum Cost to Connect Sticks | Medium | |
| 1874 | Kth Smallest Element in a Specific Array | Medium | |
| 1876 | Alien Dictionary(easy) | Easy | |
| 1877 | longest super sequence | Medium | |
| 1878 | Rotated Nums | Easy | |
| 1879 | Two Sum VII | Hard | |
| 1880 | Largest Number X Which Occurs X Times | Easy | |
| 1881 | Aircraft seat | Easy | |
| 1882 | Fair Indexes | Medium | |
| 1883 | Top K Frequently Mentioned Keywords | Medium | |
| 1884 | Take Away The Bottle | Hard | |
| 1885 | A Strange Sorting Problem | Hard | |
| 1886 | Moving Target | Easy | |
| 1887 | Stretch Word | Easy | |
| 1888 | Shortest Path in Matrix | Medium | |
| 1889 | Interval Merge | Medium | |
| 1890 | Form Minimum Number | Medium | |
| 1891 | Travel Plan | Medium | |
| 1892 | Mine-sweeping | Medium | |
| 1893 | the Valid String | Medium | |
| 1894 | Ad Click Analysis | Easy | |
| 1895 | Arrange interview city | Easy | |
| 1896 | Pick Carrots | Easy | |
| 1897 | Meeting Room III | Medium | |
| 1899 | Fetch supplies II | Medium | |
| 1900 | Gene Similarity | Hard | |
| 1901 | Squares of a Sorted Array | Easy | |
| 1902 | Find Google | Easy | |
| 1903 | Department Statistics | Easy | |
| 1904 | Put small balls | Hard | |
| 1905 | Character deletion | JavaScript | Easy |
| 1906 | Look for points that are bigger than the surrounding area | Easy | |
| 1907 | Array Game | Medium | |
| 1908 | Boolean expression evaluation | Hard | |
| 1909 | Order allocation | Medium | |
| 1914 | Smart Sale | Medium | |
| 1915 | Lifting Weights | Hard |
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