| 648 | Replace Words | | | Medium |
| 647 | Palindromic Substrings | | | Medium |
| 646 | Maximum Length of Pair Chain | | | Medium |
| 645 | Set Mismatch | | | Easy |
| 644 | Maximum Average Subarray II | | | Hard |
| 643 | Maximum Average Subarray I | | | Easy |
| 642 | Design Search Autocomplete System 📘 | | | Hard |
| 640 | Solve the Equation | | | Medium |
| 639 | Decode Ways II | | | Hard |
| 638 | Shopping Offers | | | Medium |
| 637 | Average of Levels in Binary Tree | | | Easy |
| 636 | Exclusive Time of Functions | | | Medium |
| 635 | Design Log Storage System 📘 | | | Medium |
| 634 | Find the Derangement of An Array 📘 | | | Medium |
| 633 | Sum of Square Numbers | JavaScript /Python | | Easy |
| 632 | Smallest Range | | | Hard |
| 631 | Design Excel Sum Formula 📘 | | | Hard |
| 630 | Course Schedule III | | | Hard |
| 629 | K Inverse Pairs Array | | | Hard |
| 628 | Maximum Product of Three Numbers | | | Easy |
| 625 | Minimum Factorization 📘 | | | Medium |
| 624 | Maximum Distance in Arrays 📘 | | | Easy |
| 623 | Add One Row to Tree | | | Medium |
| 621 | Task Scheduler | | | Medium |
| 617 | Merge Two Binary Trees | | | Easy |
| 616 | Add Bold Tag in String 📘 | | | Medium |
| 611 | Valid Triangle Number | | | Medium |
| 609 | Find Duplicate File in System | | | Medium |
| 606 | Construct String from Binary Tree | | | Easy |
| 605 | Can Place Flowers | | | Easy |
| 604 | Design Compressed String Iterator 📘 | | | Easy |
| 600 | Non-negative Integers without Consecutive Ones | | | Hard |
| 599 | Minimum Index Sum of Two Lists | | | Easy |
| 598 | Range Addition II | | | Easy |
| 594 | Longest Harmonious Subsequence | | | Easy |
| 593 | Valid Square | | | Medium |
| 592 | Fraction Addition and Subtraction | | | Medium |
| 591 | Tag Validator | | | Hard |
| 588 | Design In-Memory File System 📘 | | | Hard |
| 587 | Erect the Fence | | | Hard |
| 583 | Delete Operation for Two Strings | | | Medium |
| 582 | Kill Process 📘 | | | Medium |
| 581 | Shortest Unsorted Continuous Subarray | | | Easy |
| 576 | Out of Boundary Paths | | | Medium |
| 575 | Distribute Candies | | | Easy |
| 573 | Squirrel Simulation 📘 | | | Medium |
| 572 | Subtree of Another Tree | | | Easy |
| 568 | Maximum Vacation Days 📘 | | | Hard |
| 567 | Permutation in String | | | Medium |
| 566 | Reshape the Matrix | | | Easy |
| 565 | Array Nesting | | | Medium |
| 564 | Find the Closest Palindrome | | | Hard |
| 563 | Binary Tree Tilt | | | Easy |
| 562 | Longest Line of Consecutive One in Matrix 📘 | | | Medium |
| 561 | Array Partition I | | | Easy |
| 560 | Subarray Sum Equals K | | | Medium |
| 557 | Reverse Words in a String III | | | Easy |
| 556 | Next Greater Element III | | | Medium |
| 555 | Split Concatenated Strings 📘 | | | Medium |
| 554 | Brick Wall | | | Medium |
| 553 | Optimal Division | | | Medium |
| 552 | Student Attendance Record II | | | Hard |
| 551 | Student Attendance Record I | | | Easy |
| 549 | Binary Tree Longest Consecutive Sequence II 📘 | | | Medium |
| 548 | Split Array with Equal Sum 📘 | | | Medium |
| 547 | Friend Circles | Python | | Medium |
| 546 | Remove Boxes | | | Hard |
| 545 | Boundary of Binary Tree 📘 | | | Medium |
| 544 | Output Contest Matches 📘 | | | Medium |
| 543 | Diameter of Binary Tree | Python | | Easy |
| 542 | 01 Matrix | JavaScript | | Medium |
| 541 | Reverse String II | Python | | Easy |
| 540 | Single Element in a Sorted Array | | | Medium |
| 539 | Minimum Time Difference | JavaScript | | Medium |
| 538 | Convert BST to Greater Tree | Python | | Easy |
| 537 | Complex Number Multiplication | Python | | Medium |
| 536 | Construct Binary Tree from String 📘 | | | Medium |
| 535 | Encode and Decode TinyURL | JavaScript | | Medium |
| 533 | Lonely Pixel II 📘 | Python | | Medium |
| 532 | K-diff Pairs in an Array | Python | | Easy |
| 531 | Lonely Pixel I 📘 | Python | | Medium |
| 530 | Minimum Absolute Difference in BST | Python | | Easy |
| 529 | Minesweeper | Python | | Medium |
| 527 | Word Abbreviation 📘 | | | Hard |
| 526 | Beautiful Arrangement | JavaScript | | Medium |
| 525 | Contiguous Array | | | Medium |
| 524 | Longest Word in Dictionary through Deleting | | | Medium |
| 523 | Continuous Subarray Sum | Python | Explanation | Medium |
| 522 | Longest Uncommon Subsequence II | | | Medium |
| 521 | Longest Uncommon Subsequence I | Python | | Easy |
| 520 | Detect Capital | JavaScript | | Easy |
| 517 | Super Washing Machines | | | Hard |
| 516 | Longest Palindromic Subsequence | | | Medium |
| 515 | Find Largest Value in Each Tree Row | JavaScript | | Medium |
| 514 | Freedom Trail | | | Hard |
| 513 | Find Bottom Left Tree Value | JavaScript | | Medium |
| 508 | Most Frequent Subtree Sum | JavaScript | | Medium |
| 507 | Perfect Number | Python | | Easy |
| 506 | Relative Ranks | JavaScript | | Easy |
| 505 | The Maze II 📘 | | | Medium |
| 504 | Base 7 | JavaScript | | Easy |
| 503 | Next Greater Element II | JavaScript | | Medium |
| 502 | IPO | JavaScript | | Hard |
| 501 | Find Mode in Binary Search Tree | JavaScript | | Easy |
| 500 | Keyboard Row | JavaScript | | Easy |
| 499 | The Maze III 📘 | | | Hard |
| 498 | Diagonal Traverse | JavaScript | | Medium |
| 496 | Next Greater Element I | JavaScript | | Easy |
| 495 | Teemo Attacking | JavaScript | | Medium |
| 494 | Target Sum | JavaScript | Explanation | Medium |
| 493 | Reverse Pairs | | | Hard |
| 492 | Construct the Rectangle | JavaScript | | Easy |
| 491 | Increasing Subsequences | JavaScript | | Medium |
| 490 | The Maze 📘 | | | Medium |
| 488 | Zuma Game | | | Hard |
| 487 | Max Consecutive Ones II 📘 | | | Medium |
| 486 | Predict the Winner | JavaScript | Explanation | Medium |
| 485 | Max Consecutive Ones | JavaScript | | Easy |
| 484 | Find Permutation 📘 | | | Medium |
| 483 | Smallest Good Base | | | Hard |
| 482 | License Key Formatting | JavaScript | | Medium |
| 481 | Magical String | JavaScript | | Medium |
| 480 | Sliding Window Median | JavaScript | | Hard |
| 479 | Largest Palindrome Product | | | Easy |
| 477 | Total Hamming Distance | JavaScript | | Medium |
| 476 | Number Complement | JavaScript | | Easy |
| 475 | Heaters | JavaScript | | Easy |
| 474 | Ones and Zeroes | JavaScript | | Medium |
| 473 | Matchsticks to Square | JavaScript | Explanation | Medium |
| 472 | Concatenated Words | | | Hard |
| 471 | Encode String with Shortest Length 📘 | | | Hard |
| 469 | Convex Polygon 📘 | | | Medium |
| 468 | Validate IP Address | JavaScript | | Medium |
| 467 | Unique Substrings in Wraparound String | | | Medium |
| 466 | Count The Repetitions | | | Hard |
| 465 | Optimal Account Balancing 📘 | | | Hard |
| 464 | Can I Win | | | Medium |
| 463 | Island Perimeter | JavaScript | | Easy |
| 462 | Minimum Moves to Equal Array Elements II | JavaScript | Explanation | Medium |
| 461 | Hamming Distance | JavaScript | | Easy |
| 460 | LFU Cache | | | Hard |
| 459 | Repeated Substring Pattern | JavaScript | | Easy |
| 456 | 132 Pattern | | | Medium |
| 455 | Assign Cookies | JavaScript | | Easy |
| 454 | 4Sum II | JavaScript | | Medium |
| 453 | Minimum Moves to Equal Array Elements | JavaScript | Explanation | Easy |
| 452 | Minimum Number of Arrows to Burst Balloons | JavaScript | | Medium |
| 451 | Sort Characters By Frequency | JavaScript | | Medium |
| 450 | Delete Node in a BST | | | Medium |
| 449 | Serialize and Deserialize BST | | | Medium |
| 448 | Find All Numbers Disappeared in an Array | JavaScript | | Easy |
| 447 | Number of Boomerangs | JavaScript | | Easy |
| 446 | Arithmetic Slices II - Subsequence | | | Hard |
| 445 | Add Two Numbers II | JavaScript | | Medium |
| 444 | Sequence Reconstruction 📘 | | | Medium |
| 442 | Find All Duplicates in an Array | JavaScript | | Medium |
| 441 | Arranging Coins | JavaScript | | Easy |
| 440 | K-th Smallest in Lexicographical Order | | | Hard |
| 439 | Ternary Expression Parser 📘 | | | Medium |
| 438 | Find All Anagrams in a String | JavaScript | Explanation | Easy |
| 437 | Path Sum III | JavaScript | Explanation | Easy |
| 436 | Find Right Interval | JavaScript | | Medium |
| 435 | Non-overlapping Intervals | JavaScript | | Medium |
| 434 | Number of Segments in a String | JavaScript | | Easy |
| 432 | All O`one Data Structure | | | Hard |
| 425 | Word Squares 📘 | | | Hard |
| 424 | Longest Repeating Character Replacement | | | Medium |
| 423 | Reconstruct Original Digits from English | JavaScript | | Medium |
| 422 | Valid Word Square 📘 | | | Easy |
| 421 | Maximum XOR of Two Numbers in an Array | JavaScript | Explanation | Medium |
| 420 | Strong Password Checker | | | Hard |
| 419 | Battleships in a Board | JavaScript | | Medium |
| 418 | Sentence Screen Fitting 📘 | | | Medium |
| 417 | Pacific Atlantic Water Flow | JavaScript | | Medium |
| 416 | Partition Equal Subset Sum | | | Medium |
| 415 | Add Strings | JavaScript | | Easy |
| 414 | Third Maximum Number | JavaScript | | Easy |
| 413 | Arithmetic Slices | JavaScript | | Medium |
| 412 | Fizz Buzz | JavaScript | | Easy |
| 411 | Minimum Unique Word Abbreviation 📘 | | | Hard |
| 410 | Split Array Largest Sum | | | Hard |
| 409 | Longest Palindrome | JavaScript | | Easy |
| 408 | Valid Word Abbreviation 📘 | | | Easy |
| 407 | Trapping Rain Water II | | | Hard |
| 406 | Queue Reconstruction by Height | JavaScript | | Medium |
| 405 | Convert a Number to Hexadecimal | JavaScript | | Easy |
| 404 | Sum of Left Leaves | JavaScript | | Easy |
| 403 | Frog Jump | | | Hard |
| 402 | Remove K Digits | JavaScript | Explanation | Medium |
| 401 | Binary Watch | JavaScript | | Easy |
| 400 | Nth Digit | JavaScript | | Easy |
| 399 | Evaluate Division | | | Medium |
| 398 | Random Pick Index | Python | | Medium |
| 397 | Integer Replacement | JavaScript | | Medium |
| 396 | Rotate Function | JavaScript | | Medium |
| 395 | Longest Substring with At Least K Repeating Characters | JavaScript | Explanation | Medium |
| 394 | Decode String | JavaScript | | Medium |
| 393 | UTF-8 Validation | JavaScript | | Medium |
| 392 | Is Subsequence | JavaScript | | Medium |
| 391 | Perfect Rectangle | | | Hard |
| 390 | Elimination Game | | | Medium |
| 389 | Find the Difference | JavaScript | | Easy |
| 388 | Longest Absolute File Path | JavaScript | | Medium |
| 387 | First Unique Character in a String | JavaScript | | Easy |
| 386 | Lexicographical Numbers | JavaScript | | Medium |
| 385 | Mini Parser | JavaScript | | Medium |
| 384 | Shuffle an Array | JavaScript | | Medium |
| 383 | Ransom Note | JavaScript | | Easy |
| 382 | Linked List Random Node | JavaScript | | Medium |
| 381 | Insert Delete GetRandom O(1) - Duplicates allowed | Python | | Hard |
| 380 | Insert Delete GetRandom O(1) | Python | | Medium |
| 379 | Design Phone Directory 📘 | | | Medium |
| 378 | Kth Smallest Element in a Sorted Matrix | JavaScript | | Medium |
| 377 | Combination Sum IV | JavaScript | | Medium |
| 376 | Wiggle Subsequence | JavaScript | | Medium |
| 375 | Guess Number Higher or Lower II | JavaScript | | Medium |
| 374 | Guess Number Higher or Lower | C++ | | Easy |
| 373 | Find K Pairs with Smallest Sums | JavaScript | | Medium |
| 372 | Super Pow | JavaScript | | Medium |
| 371 | Sum of Two Integers | JavaScript | | Easy |
| 370 | Range Addition 📘 | | | Medium |
| 369 | Plus One Linked List 📘 | | | Medium |
| 368 | Largest Divisible Subset | JavaScript | | Medium |
| 367 | Valid Perfect Square | JavaScript | | Easy |
| 366 | Find Leaves of Binary Tree 📘 | | | Medium |
| 365 | Water and Jug Problem | | | Medium |
| 364 | Nested List Weight Sum II 📘 | | | Medium |
| 363 | Max Sum of Rectangle No Larger Than K | | | Hard |
| 362 | Design Hit Counter 📘 | | | Medium |
| 361 | Bomb Enemy 📘 | | | Medium |
| 360 | Sort Transformed Array 📘 | | | Medium |
| 359 | Logger Rate Limiter 📘 | | | Easy |
| 358 | Rearrange String k Distance Apart 📘 | | | Hard |
| 357 | Count Numbers with Unique Digits | JavaScript | | Medium |
| 356 | Line Reflection 📘 | | | Medium |
| 355 | Design Twitter | | | Medium |
| 354 | Russian Doll Envelopes | | | Hard |
| 353 | Design Snake Game 📘 | | | Medium |
| 352 | Data Stream as Disjoint Intervals | | | Hard |
| 351 | Android Unlock Patterns 📘 | | | Medium |
| 350 | Intersection of Two Arrays II | JavaScript | | Easy |
| 349 | Intersection of Two Arrays | JavaScript | | Easy |
| 348 | Design Tic-Tac-Toe 📘 | | | Medium |
| 347 | Top K Frequent Elements | JavaScript | Explanation | Medium |
| 346 | Moving Average from Data Stream 📘 | | | Easy |
| 345 | Reverse Vowels of a String | JavaScript | Explanation | Easy |
| 344 | Reverse String | JavaScript | Explanation | Easy |
| 343 | Integer Break | JavaScript | Explanation | Medium |
| 342 | Power of Four | JavaScript | Explanation | Easy |
| 341 | Flatten Nested List Iterator | JavaScript | Explanation | Medium |
| 340 | Longest Substring with At Most K Distinct Characters 📘 | | | Hard |
| 339 | Nested List Weight Sum 📘 | | | Easy |
| 338 | Counting Bits | JavaScript | Explanation | Medium |
| 337 | House Robber III | JavaScript | Explanation | Medium |
| 336 | Palindrome Pairs | JavaScript | | Hard |
| 335 | Self Crossing | JavaScript | Explanation | Hard |
| 334 | Increasing Triplet Subsequence | JavaScript | Explanation | Medium |
| 333 | Largest BST Subtree 📘 | | | Medium |
| 332 | Reconstruct Itinerary | | | Medium |
| 331 | Verify Preorder Serialization of a Binary Tree | JavaScript | | Medium |
| 330 | Patching Array | JavaScript | Explanation | Hard |
| 329 | Longest Increasing Path in a Matrix | | | Hard |
| 328 | Odd Even Linked List | JavaScript | | Medium |
| 327 | Count of Range Sum | JavaScript | | Hard |
| 326 | Power of Three | JavaScript | Explanation | Easy |
| 325 | Maximum Size Subarray Sum Equals k 📘 | | | Medium |
| 324 | Wiggle Sort II | | | Medium |
| 323 | Number of Connected Components in an Undirected Graph 📘 | | | Medium |
| 322 | Coin Change | JavaScript | Explanation | Medium |
| 321 | Create Maximum Number | | | Hard |
| 320 | Generalized Abbreviation 📘 | | | Medium |
| 319 | Bulb Switcher | JavaScript | Explanation | Medium |
| 318 | Maximum Product of Word Lengths | JavaScript | | Medium |
| 317 | Shortest Distance from All Buildings 📘 | | | Hard |
| 316 | Remove Duplicate Letters | | | Hard |
| 315 | Count of Smaller Numbers After Self | JavaScript | Explanation | Hard |
| 314 | Binary Tree Vertical Order Traversal 📘 | | | Medium |
| 313 | Super Ugly Number | JavaScript | Explanation | Medium |
| 312 | Burst Balloons | | | Hard |
| 311 | Sparse Matrix Multiplication 📘 | | | Medium |
| 310 | Minimum Height Trees | | | Medium |
| 309 | Best Time to Buy and Sell Stock with Cooldown | JavaScript | Explanation | Medium |
| 308 | Range Sum Query 2D - Mutable 📘 | | | Hard |
| 307 | Range Sum Query - Mutable | JavaScript | Explanation | Medium |
| 306 | Additive Number | JavaScript | Explanation | Medium |
| 305 | Number of Islands II 📘 | | | Hard |
| 304 | Range Sum Query 2D - Immutable | JavaScript | Explanation | Medium |
| 303 | Range Sum Query - Immutable | JavaScript | Explanation | Easy |
| 302 | Smallest Rectangle Enclosing Black Pixels 📘 | | | Hard |
| 301 | Remove Invalid Parentheses | | | Hard |
| 300 | Longest Increasing Subsequence | JavaScript | Explanation | Medium |
| 299 | Bulls and Cows | JavaScript | Explanation | Medium |
| 298 | Binary Tree Longest Consecutive Sequence 📘 | | | Medium |
| 297 | Serialize and Deserialize Binary Tree | | | Hard |
| 296 | Best Meeting Point 📘 | | | Hard |
| 295 | Find Median from Data Stream | JavaScript | Explanation | Hard |
| 294 | Flip Game II 📘 | | | Medium |
| 293 | Flip Game 📘 | | | Easy |
| 292 | Nim Game | JavaScript | Explanation | Easy |
| 291 | Word Pattern II 📘 | | | Hard |
| 290 | Word Pattern | JavaScript | Explanation | Easy |
| 289 | Game of Life | JavaScript | Explanation | Medium |
| 288 | Unique Word Abbreviation 📘 | | | Medium |
| 287 | Find the Duplicate Number | JavaScript | Explanation | Medium |
| 286 | Walls and Gates 📘 | | | Medium |
| 285 | Inorder Successor in BST 📘 | | | Medium |
| 284 | Peeking Iterator | | | Medium |
| 283 | Move Zeroes | JavaScript | Explanation | Easy |
| 282 | Expression Add Operators | | | Hard |
| 281 | Zigzag Iterator 📘 | | | Medium |
| 280 | Wiggle Sort 📘 | | | Medium |
| 279 | Perfect Squares | JavaScript | Explanation | Medium |
| 278 | First Bad Version | JavaScript | Explanation | Easy |
| 277 | Find the Celebrity 📘 | | | Medium |
| 276 | Paint Fence 📘 | | | Easy |
| 275 | H-Index II | JavaScript | Explanation | Medium |
| 274 | H-Index | JavaScript | Explanation | Medium |
| 273 | Integer to English Words | | | Hard |
| 272 | Closest Binary Search Tree Value II 📘 | | | Hard |
| 271 | Encode and Decode Strings 📘 | | | Medium |
| 270 | Closest Binary Search Tree Value 📘 | | | Easy |
| 269 | Alien Dictionary 📘 | | | Hard |
| 268 | Missing Number | JavaScript | Explanation | Easy |
| 267 | Palindrome Permutation II 📘 | | | Medium |
| 266 | Palindrome Permutation 📘 | | | Easy |
| 265 | Paint House II 📘 | | | Hard |
| 264 | Ugly Number II | JavaScript | Explanation | Medium |
| 263 | Ugly Number | JavaScript | Explanation | Easy |
| 261 | Graph Valid Tree 📘 | | | Medium |
| 260 | Single Number III | JavaScript | | Medium |
| 259 | 3Sum Smaller 📘 | | | Medium |
| 258 | Add Digits | JavaScript | Explanation | Easy |
| 257 | Binary Tree Paths | JavaScript | Explanation | Easy |
| 256 | Paint House 📘 | | | Easy |
| 255 | Verify Preorder Sequence in Binary Search Tree 📘 | | | Medium |
| 254 | Factor Combinations 📘 | | | Medium |
| 253 | Meeting Rooms II 📘 | | | Medium |
| 252 | Meeting Rooms 📘 | | | Easy |
| 251 | Flatten 2D Vector 📘 | | | Medium |
| 250 | Count Univalue Subtrees 📘 | | | Medium |
| 249 | Group Shifted Strings 📘 | | | Medium |
| 248 | Strobogrammatic Number III 📘 | | | Hard |
| 247 | Strobogrammatic Number II 📘 | | | Medium |
| 246 | Strobogrammatic Number 📘 | | | Easy |
| 245 | Shortest Word Distance III 📘 | | | Medium |
| 244 | Shortest Word Distance II 📘 | | | Medium |
| 243 | Shortest Word Distance 📘 | | | Easy |
| 242 | Valid Anagram | JavaScript | Explanation | Easy |
| 241 | Different Ways to Add Parentheses | JavaScript | Explanation | Medium |
| 240 | Search a 2D Matrix II | JavaScript | Explanation | Medium |
| 239 | Sliding Window Maximum | | | Hard |
| 238 | Product of Array Except Self | JavaScript | | Medium |
| 237 | Delete Node in a Linked List | JavaScript | Explanation | Easy |
| 236 | Lowest Common Ancestor of a Binary Tree | JavaScript | Explanation | Medium |
| 235 | Lowest Common Ancestor of a Binary Search Tree | JavaScript | | Easy |
| 234 | Palindrome Linked List | JavaScript | Explanation | Easy |
| 233 | Number of Digit One | JavaScript | | Hard |
| 232 | Implement Queue using Stacks | JavaScript | Explanation | Easy |
| 231 | Power of Two | JavaScript | Explanation | Easy |
| 230 | Kth Smallest Element in a BST | JavaScript | Explanation | Medium |
| 229 | Majority Element II | JavaScript | | Medium |
| 228 | Summary Ranges | JavaScript | Explanation | Medium |
| 227 | Basic Calculator II | JavaScript | | Medium |
| 226 | Invert Binary Tree | JavaScript | Explanation | Easy |
| 225 | Implement Stack using Queues | JavaScript | Explanation | Easy |
| 224 | Basic Calculator | JavaScript | Explanation | Hard |
| 223 | Rectangle Area | JavaScript | Explanation | Medium |
| 222 | Count Complete Tree Nodes | JavaScript | Explanation | Medium |
| 221 | Maximal Square | JavaScript | | Medium |
| 220 | Contains Duplicate III | JavaScript | | Medium |
| 219 | Contains Duplicate II | JavaScript | | Easy |
| 218 | The Skyline Problem | | | Hard |
| 217 | Contains Duplicate | JavaScript | | Easy |
| 216 | Combination Sum III | JavaScript | | Medium |
| 215 | Kth Largest Element in an Array | JavaScript | Explanation | Medium |
| 214 | Shortest Palindrome | JavaScript | Explanation | Hard |
| 213 | House Robber II | JavaScript | | Medium |
| 212 | Word Search II | | | Hard |
| 211 | Add and Search Word - Data structure design | JavaScript | Explanation | Medium |
| 210 | Course Schedule II | JavaScript | | Medium |
| 209 | Minimum Size Subarray Sum | JavaScript | | Medium |
| 208 | Implement Trie (Prefix Tree) | JavaScript | | Medium |
| 207 | Course Schedule | JavaScript | Explanation | Medium |
| 206 | Reverse Linked List | JavaScript | | Easy |
| 205 | Isomorphic Strings | JavaScript | Explanation | Easy |
| 204 | Count Primes | JavaScript | Explanation | Easy |
| 203 | Remove Linked List Elements | JavaScript | Explanation | Easy |
| 202 | Happy Number | JavaScript | Explanation | Easy |
| 201 | Bitwise AND of Numbers Range | JavaScript | | Medium |
| 200 | Number of Islands | JavaScript | Explanation | Medium |
| 199 | Binary Tree Right Side View | JavaScript | | Medium |
| 198 | House Robber | JavaScript | | Easy |
| 191 | Number of 1 Bits | JavaScript | | Easy |
| 190 | Reverse Bits | JavaScript | Explanation | Easy |
| 189 | Rotate Array | JavaScript | Explanation | Easy |
| 188 | Best Time to Buy and Sell Stock IV | | | Hard |
| 187 | Repeated DNA Sequences | JavaScript | Explanation | Medium |
| 186 | Reverse Words in a String II 📘 | | | Medium |
| 179 | Largest Number | JavaScript | Explanation | Medium |
| 174 | Dungeon Game | | | Hard |
| 173 | Binary Search Tree Iterator | | | Medium |
| 172 | Factorial Trailing Zeroes | JavaScript | Explanation | Easy |
| 171 | Excel Sheet Column Number | JavaScript | Explanation | Easy |
| 170 | Two Sum III - Data structure design 📘 | | | Easy |
| 169 | Majority Element | JavaScript | Explanation | Easy |
| 168 | Excel Sheet Column Title | JavaScript | Explanation | Easy |
| 167 | Two Sum II - Input array is sorted | JavaScript | | Easy |
| 166 | Fraction to Recurring Decimal | JavaScript | Explanation | Medium |
| 165 | Compare Version Numbers | JavaScript | Explanation | Medium |
| 164 | Maximum Gap | JavaScript | Explanation | Hard |
| 163 | Missing Ranges 📘 | | | Medium |
| 162 | Find Peak Element | JavaScript | Explanation | Medium |
| 161 | One Edit Distance 📘 | | | Medium |
| 160 | Intersection of Two Linked Lists | JavaScript | | Easy |
| 159 | Longest Substring with At Most Two Distinct Characters 📘 | | | Hard |
| 158 | Read N Characters Given Read4 II - Call multiple times 📘 | | | Hard |
| 157 | Read N Characters Given Read4 📘 | | | Easy |
| 156 | Binary Tree Upside Down 📘 | | | Medium |
| 155 | Min Stack | | | Easy |
| 154 | Find Minimum in Rotated Sorted Array II | JavaScript | | Hard |
| 153 | Find Minimum in Rotated Sorted Array | JavaScript | | Medium |
| 152 | Maximum Product Subarray | JavaScript | | Medium |
| 151 | Reverse Words in a String | JavaScript | Explanation | Medium |
| 150 | Evaluate Reverse Polish Notation | | | Medium |
| 149 | Max Points on a Line | | | Hard |
| 148 | Sort List | JavaScript | Explanation | Medium |
| 147 | Insertion Sort List | JavaScript | | Medium |
| 146 | LRU Cache | JavaScript | Explanation | Hard |
| 145 | Binary Tree Postorder Traversal | JavaScript | | Hard |
| 144 | Binary Tree Preorder Traversal | JavaScript | | Medium |
| 143 | Reorder List | JavaScript | | Medium |
| 142 | Linked List Cycle II | JavaScript | | Medium |
| 141 | Linked List Cycle | JavaScript | Explanation | Easy |
| 140 | Word Break II | | | Hard |
| 139 | Word Break | JavaScript | | Medium |
| 138 | Copy List with Random Pointer | JavaScript | | Medium |
| 137 | Single Number II | JavaScript | | Medium |
| 136 | Single Number | JavaScript | | Easy |
| 135 | Candy | | | Hard |
| 134 | Gas Station | | | Medium |
| 133 | Clone Graph | JavaScript | | Medium |
| 132 | Palindrome Partitioning II | JavaScript | Explanation | Hard |
| 131 | Palindrome Partitioning | JavaScript | Explanation | Medium |
| 130 | Surrounded Regions | | | Medium |
| 129 | Sum Root to Leaf Numbers | JavaScript | | Medium |
| 128 | Longest Consecutive Sequence | JavaScript | | Hard |
| 127 | Word Ladder | | | Medium |
| 126 | Word Ladder II | | | Hard |
| 125 | Valid Palindrome | JavaScript | Explanation | Easy |
| 124 | Binary Tree Maximum Path Sum | | | Hard |
| 123 | Best Time to Buy and Sell Stock III | JavaScript | | Hard |
| 122 | Best Time to Buy and Sell Stock II | JavaScript | Explanation | Easy |
| 121 | Best Time to Buy and Sell Stock | JavaScript | Explanation | Easy |
| 120 | Triangle | JavaScript | | Medium |
| 119 | Pascal's Triangle II | JavaScript | Explanation | Easy |
| 118 | Pascal's Triangle | JavaScript | Explanation | Easy |
| 117 | Populating Next Right Pointers in Each Node II | JavaScript | | Medium |
| 116 | Populating Next Right Pointers in Each Node | JavaScript | | Medium |
| 115 | Distinct Subsequences | | | Hard |
| 114 | Flatten Binary Tree to Linked List | JavaScript | Explanation | Medium |
| 113 | Path Sum II | JavaScript | | Medium |
| 112 | Path Sum | JavaScript | | Easy |
| 111 | Minimum Depth of Binary Tree | JavaScript | | Easy |
| 110 | Balanced Binary Tree | JavaScript | | Easy |
| 109 | Convert Sorted List to Binary Search Tree | JavaScript | | Medium |
| 108 | Convert Sorted Array to Binary Search Tree | JavaScript | | Easy |
| 107 | Binary Tree Level Order Traversal II | JavaScript | | Easy |
| 106 | Construct Binary Tree from Inorder and Postorder Traversal | JavaScript | | Medium |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | JavaScript | | Medium |
| 104 | Maximum Depth of Binary Tree | JavaScript | | Easy |
| 103 | Binary Tree Zigzag Level Order Traversal | JavaScript | | Medium |
| 102 | Binary Tree Level Order Traversal | JavaScript | | Medium |
| 101 | Symmetric Tree | JavaScript | | Easy |
| 100 | Same Tree | JavaScript | | Easy |
| 99 | Recover Binary Search Tree | | | Hard |
| 98 | Validate Binary Search Tree | JavaScript | | Medium |
| 97 | Interleaving String | | | Hard |
| 96 | Unique Binary Search Trees | JavaScript | | Medium |
| 95 | Unique Binary Search Trees II | JavaScript | | Medium |
| 94 | Binary Tree Inorder Traversal | JavaScript | | Medium |
| 93 | Restore IP Addresses | JavaScript | | Medium |
| 92 | Reverse Linked List II | JavaScript | | Medium |
| 91 | Decode Ways | JavaScript | | Medium |
| 90 | Subsets II | JavaScript | | Medium |
| 89 | Gray Code | JavaScript | | Medium |
| 88 | Merge Sorted Array | JavaScript | Explanation | Easy |
| 87 | Scramble String | | | Hard |
| 86 | Partition List | JavaScript | Explanation | Medium |
| 85 | Maximal Rectangle | JavaScript | | Hard |
| 84 | Largest Rectangle in Histogram | JavaScript | | Hard |
| 83 | Remove Duplicates from Sorted List | JavaScript | | Easy |
| 82 | Remove Duplicates from Sorted List II | JavaScript | | Medium |
| 81 | Search in Rotated Sorted Array II | JavaScript | | Medium |
| 80 | Remove Duplicates from Sorted Array II | JavaScript | Explanation | Medium |
| 79 | Word Search | JavaScript | | Medium |
| 78 | Subsets | JavaScript | | Medium |
| 77 | Combinations | JavaScript | | Medium |
| 76 | Minimum Window Substring | | | Hard |
| 75 | Sort Colors | JavaScript | Explanation | Medium |
| 74 | Search a 2D Matrix | JavaScript | | Medium |
| 73 | Set Matrix Zeroes | JavaScript | Explanation | Medium |
| 72 | Edit Distance | | | Hard |
| 71 | Simplify Path | JavaScript | | Medium |
| 70 | Climbing Stairs | JavaScript | Explanation | Easy |
| 69 | Sqrt(x) | JavaScript | Explanation | Easy |
| 68 | Text Justification | | | Hard |
| 67 | Add Binary | JavaScript | Explanation | Easy |
| 66 | Plus One | JavaScript | Explanation | Easy |
| 65 | Valid Number | JavaScript | Explanation | Hard |
| 64 | Minimum Path Sum | JavaScript | | Medium |
| 63 | Unique Paths II | JavaScript | Explanation | Medium |
| 62 | Unique Paths | JavaScript | Explanation | Medium |
| 61 | Rotate List | JavaScript | Explanation | Medium |
| 60 | Permutation Sequence | JavaScript | | Medium |
| 59 | Spiral Matrix II | JavaScript | | Medium |
| 58 | Length of Last Word | JavaScript | Explanation | Easy |
| 57 | Insert Interval | JavaScript | | Hard |
| 56 | Merge Intervals | JavaScript | | Medium |
| 55 | Jump Game | JavaScript | | Medium |
| 54 | Spiral Matrix | JavaScript | | Medium |
| 53 | Maximum Subarray | JavaScript | | Easy |
| 52 | N-Queens II | JavaScript | | Hard |
| 51 | N-Queens | JavaScript | | Hard |
| 50 | Pow(x, n) | JavaScript | Explanation | Medium |
| 49 | Group Anagrams | JavaScript | | Medium |
| 48 | Rotate Image | JavaScript | | Medium |
| 47 | Permutations II | JavaScript | | Medium |
| 46 | Permutations | JavaScript | | Medium |
| 45 | Jump Game II | JavaScript | | Hard |
| 44 | Wildcard Matching | | | Hard |
| 43 | Multiply Strings | JavaScript | | Medium |
| 42 | Trapping Rain Water | JavaScript | | Hard |
| 41 | First Missing Positive | JavaScript | Explanation | Hard |
| 40 | Combination Sum II | JavaScript | | Medium |
| 39 | Combination Sum | JavaScript | | Medium |
| 38 | Count and Say | JavaScript | Explanation | Easy |
| 37 | Sudoku Solver | | | Hard |
| 36 | Valid Sudoku | JavaScript | | Medium |
| 35 | Search Insert Position | JavaScript | Explanation | Easy |
| 34 | Search for a Range | JavaScript | Explanation | Medium |
| 33 | Search in Rotated Sorted Array | JavaScript | | Medium |
| 32 | Longest Valid Parentheses | | | Hard |
| 31 | Next Permutation | JavaScript | | Medium |
| 30 | Substring with Concatenation of All Words | | | Hard |
| 29 | Divide Two Integers | JavaScript | Explanation | Medium |
| 28 | Implement strStr() | JavaScript | Explanation | Easy |
| 27 | Remove Element | JavaScript | Explanation | Easy |
| 26 | Remove Duplicates from Sorted Array | JavaScript | Explanation | Easy |
| 25 | Reverse Nodes in k-Group | JavaScript | | Hard |
| 24 | Swap Nodes in Pairs | JavaScript | Explanation | Medium |
| 23 | Merge k Sorted Lists | JavaScript | | Hard |
| 22 | Generate Parentheses | JavaScript | | Medium |
| 21 | Merge Two Sorted Lists | JavaScript | Explanation | Easy |
| 20 | Valid Parentheses | JavaScript | Explanation | Easy |
| 19 | Remove Nth Node From End of List | JavaScript | Explanation | Medium |
| 18 | 4Sum | JavaScript | | Medium |
| 17 | Letter Combinations of a Phone Number | JavaScript | Explanation | Medium |
| 16 | 3Sum Closest | JavaScript | | Medium |
| 15 | 3Sum | JavaScript | | Medium |
| 14 | Longest Common Prefix | JavaScript | Explanation | Easy |
| 13 | Roman to Integer | JavaScript | | Easy |
| 12 | Integer to Roman | JavaScript | | Medium |
| 11 | Container With Most Water | JavaScript | | Medium |
| 10 | Regular Expression Matching | JavaScript | Explanation | Hard |
| 9 | Palindrome Number | JavaScript | Explanation | Easy |
| 8 | String to Integer (atoi) | JavaScript | | Medium |
| 7 | Reverse Integer | JavaScript | Explanation | Easy |
| 6 | ZigZag Conversion | JavaScript | Explanation | Medium |
| 5 | Longest Palindromic Substring | JavaScript | Explanation | Medium |
| 4 | Median of Two Sorted Arrays | JavaScript | | Hard |
| 3 | Longest Substring Without Repeating Characters | JavaScript | | Medium |
| 2 | Add Two Numbers | JavaScript | | Medium |
| 1 | Two Sum | JavaScript | Explanation | Easy |