1 two-sum Javascript 📝 Easy 2 add-two-numbers Javascript 📝 Medium 3 longest-substring-without-repeating-characters Javascript 📝 Medium 4 median-of-two-sorted-arrays Javascript 📝 Hard 5 longest-palindromic-substring Javascript 📝 Medium 6 zigzag-conversion Javascript 📝 Medium 7 reverse-integer Javascript 📝 Easy 8 string-to-integer-atoi Javascript Medium 9 palindrome-number Javascript 📝 Easy 10 regular-expression-matching Javascript 📝 Hard 11 container-with-most-water Javascript 📝 Medium 12 integer-to-roman Javascript Medium 13 roman-to-integer Javascript Easy 14 longest-common-prefix Javascript 📝 Easy 15 3sum Javascript Medium 16 3sum-closest Javascript Medium 17 letter-combinations-of-a-phone-number Javascript Medium 18 4sum Javascript Medium 19 remove-nth-node-from-end-of-list Javascript 📝 Medium 20 valid-parentheses Javascript Easy 21 merge-two-sorted-lists Javascript 📝 Easy 22 generate-parentheses Javascript 📝 Medium 23 merge-k-sorted-lists Javascript 📝 Hard 24 swap-nodes-in-pairs Javascript Medium 25 reverse-nodes-in-k-group Javascript Hard 26 remove-duplicates-from-sorted-array Javascript 📝 Easy 27 remove-element Javascript 📝 Easy 28 implement-strstr Javascript Cpp Easy 29 divide-two-integers Javascript Medium 30 substring-with-concatenation-of-all-words Javascript Hard 31 next-permutation Javascript 📝 Medium 32 longest-valid-parentheses Javascript 📝 Hard 33 search-in-rotated-sorted-array Javascript Medium 34 find-first-and-last-position-of-element-in-sorted-array Javascript 📝 Medium 35 search-insert-position Javascript Easy 36 valid-sudoku Javascript Medium 37 sudoku-solver Javascript Hard 38 count-and-say Javascript Easy 39 combination-sum Javascript Medium 40 combination-sum-ii Javascript Medium 41 first-missing-positive Javascript Hard 42 trapping-rain-water Javascript 📝 Hard 43 multiply-strings Javascript Medium 44 wildcard-matching Javascript Hard 45 jump-game-ii Javascript Hard 46 permutations Javascript Medium 47 permutations-ii Javascript Medium 48 rotate-image Python Javascript Medium 49 group-anagrams Javascript 📝 Medium 50 powx-n Javascript 📝 Medium 51 n-queens Javascript Hard 52 n-queens-ii Javascript Hard 53 maximum-subarray Javascript Easy 54 spiral-matrix Javascript 📝 Medium 55 jump-game Javascript 📝 Medium 56 merge-intervals Javascript 📝 Medium 57 insert-interval Javascript Hard 58 length-of-last-word Javascript Easy 59 spiral-matrix-ii Javascript Medium 60 permutation-sequence Javascript Medium 61 rotate-list Javascript Medium 62 unique-paths Javascript Medium 63 unique-paths-ii Javascript Medium 64 minimum-path-sum Javascript 📝 Medium 65 valid-number Javascript Hard 66 plus-one Javascript Easy 67 add-binary Javascript Easy 68 text-justification Javascript Hard 69 sqrtx Javascript Easy 70 climbing-stairs Javascript 📝 Easy 71 simplify-path Javascript Medium 72 edit-distance Javascript Hard 73 set-matrix-zeroes Javascript Medium 74 search-a-2d-matrix Javascript Medium 75 sort-colors Javascript Medium 76 minimum-window-substring Javascript 📝 Hard 77 combinations Javascript Medium 78 subsets Javascript Medium 79 word-search Javascript Medium 80 remove-duplicates-from-sorted-array-ii Javascript Medium 81 search-in-rotated-sorted-array-ii Javascript Medium 82 remove-duplicates-from-sorted-list-ii Javascript Medium 83 remove-duplicates-from-sorted-list Javascript 📝 Easy 84 largest-rectangle-in-histogram Javascript 📝 Hard 85 maximal-rectangle Javascript Hard 86 partition-list Javascript Medium 87 scramble-string Javascript Hard 88 merge-sorted-array Javascript Easy 89 gray-code Javascript Medium 90 subsets-ii Javascript Medium 91 decode-ways Javascript Medium 92 reverse-linked-list-ii Javascript Medium 93 restore-ip-addresses Javascript Medium 94 binary-tree-inorder-traversal Javascript 📝 Medium 95 unique-binary-search-trees-ii Javascript Medium 96 unique-binary-search-trees Javascript 📝 Medium 97 interleaving-string Javascript 📝 Hard 98 validate-binary-search-tree Javascript Medium 99 recover-binary-search-tree Javascript Hard 100 same-tree Javascript Easy 101 symmetric-tree Javascript 📝 Easy 102 binary-tree-level-order-traversal Javascript Medium 103 binary-tree-zigzag-level-order-traversal Javascript Medium 104 maximum-depth-of-binary-tree Javascript Easy 105 construct-binary-tree-from-preorder-and-inorder-traversal Javascript Medium 106 construct-binary-tree-from-inorder-and-postorder-traversal Javascript Medium 107 binary-tree-level-order-traversal-ii Javascript Easy 108 convert-sorted-array-to-binary-search-tree Javascript Easy 109 convert-sorted-list-to-binary-search-tree Javascript Medium 110 balanced-binary-tree Javascript Easy 111 minimum-depth-of-binary-tree Javascript Easy 112 path-sum Javascript Easy 113 path-sum-ii Javascript Medium 114 flatten-binary-tree-to-linked-list Javascript Medium 115 distinct-subsequences Cpp Hard 116 populating-next-right-pointers-in-each-node Cpp Medium 117 populating-next-right-pointers-in-each-node-ii Cpp Medium 118 pascals-triangle Cpp 📝 Easy 119 pascals-triangle-ii Cpp Easy 120 triangle Cpp Medium 121 best-time-to-buy-and-sell-stock Javascript Cpp 📝 Easy 122 best-time-to-buy-and-sell-stock-ii Cpp 📝 Easy 123 best-time-to-buy-and-sell-stock-iii Cpp Hard 124 binary-tree-maximum-path-sum Cpp Hard 125 valid-palindrome Cpp Easy 126 word-ladder-ii Cpp Hard 127 word-ladder Cpp Medium 128 longest-consecutive-sequence Cpp 📝 Hard 129 sum-root-to-leaf-numbers Cpp Medium 130 surrounded-regions Cpp Medium 131 palindrome-partitioning Cpp Medium 132 palindrome-partitioning-ii Cpp Hard 133 clone-graph Cpp Medium 134 gas-station Cpp Medium 135 candy Cpp 📝 Hard 136 single-number Cpp 📝 Easy 137 single-number-ii Cpp Medium 138 copy-list-with-random-pointer Cpp 📝 Medium 139 word-break Cpp 📝 Medium 140 word-break-ii Cpp 📝 Hard 141 linked-list-cycle Cpp 📝 Easy 142 linked-list-cycle-ii Cpp 📝 Medium 143 reorder-list Cpp Medium 144 binary-tree-preorder-traversal Cpp Medium 145 binary-tree-postorder-traversal Cpp Hard 146 lru-cache Cpp Hard 147 insertion-sort-list Cpp Medium 148 sort-list Cpp Medium 149 max-points-on-a-line Cpp Hard 150 evaluate-reverse-polish-notation Cpp Medium 151 reverse-words-in-a-string Cpp Medium 152 maximum-product-subarray Cpp Medium 153 find-minimum-in-rotated-sorted-array Cpp 📝 Medium 154 find-minimum-in-rotated-sorted-array-ii Cpp Hard 155 min-stack Cpp Easy 156 binary-tree-upside-down 🔒 Medium 157 read-n-characters-given-read4 🔒 Easy 158 read-n-characters-given-read4-ii-call-multiple-times 🔒 Hard 159 longest-substring-with-at-most-two-distinct-characters 🔒 Hard 160 intersection-of-two-linked-lists Cpp 📝 Easy 161 one-edit-distance 🔒 Medium 162 find-peak-element Cpp 📝 Medium 163 missing-ranges 🔒 Medium 164 maximum-gap Cpp 📝 Hard 165 compare-version-numbers Javascript Cpp Medium 166 fraction-to-recurring-decimal Cpp 📝 Medium 167 two-sum-ii-input-array-is-sorted Cpp 📝 Easy 168 excel-sheet-column-title Cpp Easy 169 majority-element Javascript Cpp 📝 Easy 170 two-sum-iii-data-structure-design 🔒 Easy 171 excel-sheet-column-number Cpp Easy 172 factorial-trailing-zeroes Cpp Easy 173 binary-search-tree-iterator Cpp Medium 174 dungeon-game Cpp Hard 179 largest-number Cpp 📝 Medium 186 reverse-words-in-a-string-ii 🔒 Medium 187 repeated-dna-sequences Cpp Medium 188 best-time-to-buy-and-sell-stock-iv Cpp Hard 189 rotate-array Javascript Cpp 📝 Easy 190 reverse-bits Javascript Cpp Easy 191 number-of-1-bits Javascript Cpp 📝 Easy 198 house-robber Cpp 📝 Easy 199 binary-tree-right-side-view Cpp 📝 Medium 200 number-of-islands Cpp 📝 Medium 201 bitwise-and-of-numbers-range Cpp Medium 202 happy-number Cpp Easy 203 remove-linked-list-elements Cpp Easy 204 count-primes Cpp Easy 205 isomorphic-strings Javascript Cpp Easy 206 reverse-linked-list Cpp 📝 Easy 207 course-schedule Cpp Medium 208 implement-trie-prefix-tree Cpp 📝 Medium 209 minimum-size-subarray-sum Cpp 📝 Medium 210 course-schedule-ii Cpp Medium 211 add-and-search-word-data-structure-design Cpp Medium 212 word-search-ii Cpp Hard 213 house-robber-ii Cpp Medium 214 shortest-palindrome Cpp 📝 Hard 215 kth-largest-element-in-an-array Cpp Medium 216 combination-sum-iii Cpp Medium 217 contains-duplicate Javascript Cpp 📝 Easy 218 the-skyline-problem Cpp Hard 219 contains-duplicate-ii Javascript Cpp 📝 Easy 220 contains-duplicate-iii Cpp 📝 Medium 221 maximal-square Cpp 📝 Medium 222 count-complete-tree-nodes Cpp Medium 223 rectangle-area Cpp Medium 224 basic-calculator Cpp Hard 225 implement-stack-using-queues Javascript 📝 Easy 226 invert-binary-tree 📝 Easy 227 basic-calculator-ii Medium 228 summary-ranges 📝 Medium 229 majority-element-ii Medium 230 kth-smallest-element-in-a-bst Medium 231 power-of-two Easy 232 implement-queue-using-stacks 📝 Easy 233 number-of-digit-one 📝 Hard 234 palindrome-linked-list Easy 235 lowest-common-ancestor-of-a-binary-search-tree Easy 236 lowest-common-ancestor-of-a-binary-tree Medium 237 delete-node-in-a-linked-list 📝 Easy 238 product-of-array-except-self Medium 239 sliding-window-maximum Hard 240 search-a-2d-matrix-ii 📝 Medium 241 different-ways-to-add-parentheses Medium 242 valid-anagram 📝 Easy 243 shortest-word-distance 🔒 📝 Easy 244 shortest-word-distance-ii 🔒 Medium 245 shortest-word-distance-iii 🔒 Medium 246 strobogrammatic-number 🔒 Easy 247 strobogrammatic-number-ii 🔒 Medium 248 strobogrammatic-number-iii 🔒 Hard 249 group-shifted-strings 🔒 Medium 250 count-univalue-subtrees 🔒 Medium 251 flatten-2d-vector 🔒 Medium 252 meeting-rooms 🔒 📝 Easy 253 meeting-rooms-ii 🔒 📝 Medium 254 factor-combinations 🔒 Medium 255 verify-preorder-sequence-in-binary-search-tree 🔒 Medium 256 paint-house 🔒 Easy 257 binary-tree-paths Easy 258 add-digits Easy 259 3sum-smaller 🔒 📝 Medium 260 single-number-iii Medium 261 graph-valid-tree 🔒 Medium 263 ugly-number Easy 264 ugly-number-ii Medium 265 paint-house-ii 🔒 Hard 266 palindrome-permutation 🔒 📝 Easy 267 palindrome-permutation-ii 🔒 📝 Medium 268 missing-number 📝 Easy 269 alien-dictionary 🔒 Hard 270 closest-binary-search-tree-value 🔒 Easy 271 encode-and-decode-strings 🔒 Medium 272 closest-binary-search-tree-value-ii 🔒 Hard 273 integer-to-english-words Hard 274 h-index 📝 Medium 275 h-index-ii Medium 276 paint-fence 🔒 Easy 277 find-the-celebrity 🔒 Medium 278 first-bad-version 📝 Easy 279 perfect-squares Medium 280 wiggle-sort 🔒 📝 Medium 281 zigzag-iterator 🔒 Medium 282 expression-add-operators 📝 Hard 283 move-zeroes 📝 Easy 284 peeking-iterator Medium 285 inorder-successor-in-bst 🔒 Medium 286 walls-and-gates 🔒 📝 Medium 287 find-the-duplicate-number 📝 Medium 288 unique-word-abbreviation 🔒 📝 Medium 289 game-of-life Medium 290 word-pattern Easy 291 word-pattern-ii 🔒 Hard 292 nim-game 📝 Easy 293 flip-game 🔒 Easy 294 flip-game-ii 🔒 Medium 295 find-median-from-data-stream 📝 Hard 296 best-meeting-point 🔒 📝 Hard 297 serialize-and-deserialize-binary-tree Hard 298 binary-tree-longest-consecutive-sequence 🔒 📝 Medium 299 bulls-and-cows Medium 300 longest-increasing-subsequence 📝 Medium 301 remove-invalid-parentheses Hard 302 smallest-rectangle-enclosing-black-pixels 🔒 📝 Hard 303 range-sum-query-immutable 📝 Easy 304 range-sum-query-2d-immutable 📝 Medium 305 number-of-islands-ii 🔒 📝 Hard 306 additive-number Medium 307 range-sum-query-mutable 📝 Medium 308 range-sum-query-2d-mutable 🔒 Hard 309 best-time-to-buy-and-sell-stock-with-cooldown Medium 310 minimum-height-trees Medium 311 sparse-matrix-multiplication 🔒 Medium 312 burst-balloons Hard 313 super-ugly-number Medium 314 binary-tree-vertical-order-traversal 🔒 Medium 315 count-of-smaller-numbers-after-self Hard 316 remove-duplicate-letters Hard 317 shortest-distance-from-all-buildings 🔒 Hard 318 maximum-product-of-word-lengths Medium 319 bulb-switcher Medium 320 generalized-abbreviation 🔒 📝 Medium 321 create-maximum-number Hard 322 coin-change 📝 Medium 323 number-of-connected-components-in-an-undirected-graph 🔒 Medium 324 wiggle-sort-ii Medium 325 maximum-size-subarray-sum-equals-k 🔒 Medium 326 power-of-three 📝 Easy 327 count-of-range-sum Hard 328 odd-even-linked-list 📝 Medium 329 longest-increasing-path-in-a-matrix 📝 Hard 330 patching-array 📝 Hard 331 verify-preorder-serialization-of-a-binary-tree Medium 332 reconstruct-itinerary Medium 333 largest-bst-subtree 🔒 Medium 334 increasing-triplet-subsequence Medium 335 self-crossing Hard 336 palindrome-pairs Hard 337 house-robber-iii Medium 338 counting-bits 📝 Medium 339 nested-list-weight-sum 🔒 📝 Easy 340 longest-substring-with-at-most-k-distinct-characters 🔒 Hard 341 flatten-nested-list-iterator Medium 342 power-of-four Easy 343 integer-break Medium 344 reverse-string Easy 345 reverse-vowels-of-a-string Easy 346 moving-average-from-data-stream 🔒 Easy 347 top-k-frequent-elements Medium 348 design-tic-tac-toe 🔒 Medium 349 intersection-of-two-arrays Easy 350 intersection-of-two-arrays-ii Easy 351 android-unlock-patterns 🔒 📝 Medium 352 data-stream-as-disjoint-intervals Hard 353 design-snake-game 🔒 Medium 354 russian-doll-envelopes Hard 355 design-twitter Medium 356 line-reflection 🔒 Medium 357 count-numbers-with-unique-digits Medium 358 rearrange-string-k-distance-apart 🔒 Hard 359 logger-rate-limiter 🔒 Easy 360 sort-transformed-array 🔒 Medium 361 bomb-enemy 🔒 Medium 362 design-hit-counter 🔒 Medium 363 max-sum-of-rectangle-no-larger-than-k Hard 364 nested-list-weight-sum-ii 🔒 Medium 365 water-and-jug-problem Medium 366 find-leaves-of-binary-tree 🔒 Medium 367 valid-perfect-square Easy 368 largest-divisible-subset Medium 369 plus-one-linked-list 🔒 Medium 370 range-addition 🔒 📝 Medium 371 sum-of-two-integers Cpp Easy 372 super-pow Medium 373 find-k-pairs-with-smallest-sums Medium 374 guess-number-higher-or-lower Cpp 📝 Easy 375 guess-number-higher-or-lower-ii 📝 Medium 376 wiggle-subsequence 📝 Medium 377 combination-sum-iv Medium 378 kth-smallest-element-in-a-sorted-matrix Medium 379 design-phone-directory 🔒 Medium 380 insert-delete-getrandom-o1 Medium 381 insert-delete-getrandom-o1-duplicates-allowed Hard 382 linked-list-random-node Medium 383 ransom-note Easy 384 shuffle-an-array 📝 Medium 385 mini-parser Medium 386 lexicographical-numbers Medium 387 first-unique-character-in-a-string Easy 388 longest-absolute-file-path Medium 389 find-the-difference Easy 390 elimination-game Medium 391 perfect-rectangle Hard 392 is-subsequence Medium 393 utf-8-validation Medium 394 decode-string Medium 395 longest-substring-with-at-least-k-repeating-characters Medium 396 rotate-function Medium 397 integer-replacement Medium 398 random-pick-index Medium 399 evaluate-division Medium 400 nth-digit Easy 401 binary-watch Easy 402 remove-k-digits Medium 403 frog-jump 📝 Hard 404 sum-of-left-leaves Easy 405 convert-a-number-to-hexadecimal Easy 406 queue-reconstruction-by-height Medium 407 trapping-rain-water-ii Hard 408 valid-word-abbreviation 🔒 Easy 409 longest-palindrome 📝 Easy 410 split-array-largest-sum 📝 Hard 411 minimum-unique-word-abbreviation 🔒 Hard 412 fizz-buzz Easy 413 arithmetic-slices 📝 Medium 414 third-maximum-number Easy 415 add-strings Easy 416 partition-equal-subset-sum Medium 417 pacific-atlantic-water-flow Medium 418 sentence-screen-fitting 🔒 Medium 419 battleships-in-a-board Medium 420 strong-password-checker Hard 421 maximum-xor-of-two-numbers-in-an-array Medium 422 valid-word-square 🔒 Easy 423 reconstruct-original-digits-from-english Medium 424 longest-repeating-character-replacement Medium 425 word-squares 🔒 Hard 432 all-oone-data-structure Hard 433 minimum-genetic-mutation Medium 434 number-of-segments-in-a-string 📝 Easy 435 non-overlapping-intervals 📝 Medium 436 find-right-interval 📝 Medium 437 path-sum-iii Easy 438 find-all-anagrams-in-a-string Easy 439 ternary-expression-parser 🔒 Medium 440 k-th-smallest-in-lexicographical-order Hard 441 arranging-coins Easy 442 find-all-duplicates-in-an-array Medium 443 string-compression 📝 Easy 444 sequence-reconstruction 🔒 Medium 445 add-two-numbers-ii Medium 446 arithmetic-slices-ii-subsequence 📝 Hard 447 number-of-boomerangs Easy 448 find-all-numbers-disappeared-in-an-array Easy 449 serialize-and-deserialize-bst Medium 450 delete-node-in-a-bst Medium 451 sort-characters-by-frequency Medium 452 minimum-number-of-arrows-to-burst-balloons Medium 453 minimum-moves-to-equal-array-elements 📝 Easy 454 4sum-ii Medium 455 assign-cookies Easy 456 132-pattern 📝 Medium 457 circular-array-loop Medium 458 poor-pigs Easy 459 repeated-substring-pattern Easy 460 lfu-cache Hard 461 hamming-distance Easy 462 minimum-moves-to-equal-array-elements-ii 📝 Medium 463 island-perimeter Easy 464 can-i-win Medium 465 optimal-account-balancing 🔒 Hard 466 count-the-repetitions 📝 Hard 467 unique-substrings-in-wraparound-string Medium 468 validate-ip-address Medium 469 convex-polygon 🔒 Medium 471 encode-string-with-shortest-length 🔒 Hard 472 concatenated-words Hard 473 matchsticks-to-square 📝 Medium 474 ones-and-zeroes 📝 Medium 475 heaters Easy 476 number-complement Easy 477 total-hamming-distance 📝 Medium 479 largest-palindrome-product Easy 480 sliding-window-median 📝 Hard 481 magical-string Medium 482 license-key-formatting Easy 483 smallest-good-base Hard 484 find-permutation 🔒 📝 Medium 485 max-consecutive-ones Easy 486 predict-the-winner 📝 Medium 487 max-consecutive-ones-ii 🔒 Medium 488 zuma-game Hard 490 the-maze 🔒 📝 Medium 491 increasing-subsequences Medium 492 construct-the-rectangle Easy 493 reverse-pairs 📝 Hard 494 target-sum 📝 Medium 495 teemo-attacking Medium 496 next-greater-element-i 📝 Easy 498 diagonal-traverse Medium 499 the-maze-iii 🔒 Hard 500 keyboard-row Easy 501 find-mode-in-binary-search-tree Easy 502 ipo Hard 503 next-greater-element-ii 📝 Medium 504 base-7 Easy 505 the-maze-ii 🔒 📝 Medium 506 relative-ranks Easy 507 perfect-number 📝 Easy 508 most-frequent-subtree-sum Medium 513 find-bottom-left-tree-value Medium 514 freedom-trail Hard 515 find-largest-value-in-each-tree-row Medium 516 longest-palindromic-subsequence Medium 517 super-washing-machines Hard 518 coin-change-2 Medium 520 detect-capital Easy 521 longest-uncommon-subsequence-i 📝 Easy 522 longest-uncommon-subsequence-ii 📝 Medium 523 continuous-subarray-sum 📝 Medium 524 longest-word-in-dictionary-through-deleting 📝 Medium 525 contiguous-array 📝 Medium 526 beautiful-arrangement 📝 Medium 527 word-abbreviation 🔒 📝 Hard 529 minesweeper Medium 530 minimum-absolute-difference-in-bst Easy 531 lonely-pixel-i 🔒 Medium 532 k-diff-pairs-in-an-array Easy 533 lonely-pixel-ii 🔒 Medium 535 encode-and-decode-tinyurl 📝 Medium 536 construct-binary-tree-from-string 🔒 Medium 537 complex-number-multiplication 📝 Medium 538 convert-bst-to-greater-tree 📝 Easy 539 minimum-time-difference Medium 540 single-element-in-a-sorted-array Medium 541 reverse-string-ii 📝 Easy 542 01-matrix 📝 Medium 543 diameter-of-binary-tree 📝 Easy 544 output-contest-matches 🔒 📝 Medium 545 boundary-of-binary-tree 🔒 📝 Medium 546 remove-boxes 📝 Hard 547 friend-circles 📝 Medium 548 split-array-with-equal-sum 🔒 📝 Medium 549 binary-tree-longest-consecutive-sequence-ii 🔒 📝 Medium 551 student-attendance-record-i 📝 Easy 552 student-attendance-record-ii 📝 Hard 553 optimal-division 📝 Medium 554 brick-wall 📝 Medium 555 split-concatenated-strings 🔒 📝 Medium 556 next-greater-element-iii 📝 Medium 557 reverse-words-in-a-string-iii 📝 Easy 560 subarray-sum-equals-k 📝 Medium 561 array-partition-i 📝 Easy 562 longest-line-of-consecutive-one-in-matrix 🔒 📝 Medium 563 binary-tree-tilt 📝 Easy 564 find-the-closest-palindrome 📝 Hard 565 array-nesting 📝 Medium 566 reshape-the-matrix 📝 Easy 567 permutation-in-string 📝 Medium 568 maximum-vacation-days 🔒 📝 Hard 572 subtree-of-another-tree 📝 Easy 573 squirrel-simulation 🔒 📝 Medium 575 distribute-candies 📝 Easy 576 out-of-boundary-paths 📝 Medium 581 shortest-unsorted-continuous-subarray 📝 Easy 582 kill-process 🔒 📝 Medium 583 delete-operation-for-two-strings 📝 Medium 587 erect-the-fence 📝 Hard 588 design-in-memory-file-system 🔒 📝 Hard 591 tag-validator 📝 Hard 592 fraction-addition-and-subtraction 📝 Medium 593 valid-square 📝 Medium 594 longest-harmonious-subsequence 📝 Easy 598 range-addition-ii 📝 Easy 599 minimum-index-sum-of-two-lists 📝 Easy 600 non-negative-integers-without-consecutive-ones 📝 Hard 604 design-compressed-string-iterator 🔒 📝 Easy 605 can-place-flowers 📝 Easy 606 construct-string-from-binary-tree 📝 Easy 609 find-duplicate-file-in-system 📝 Medium 611 valid-triangle-number 📝 Medium 616 add-bold-tag-in-string 🔒 📝 Medium 617 merge-two-binary-trees 📝 Easy 621 task-scheduler 📝 Medium 623 add-one-row-to-tree 📝 Medium 624 maximum-distance-in-arrays 🔒 📝 Easy 625 minimum-factorization 🔒 📝 Medium 628 maximum-product-of-three-numbers 📝 Easy 629 k-inverse-pairs-array 📝 Hard 630 course-schedule-iii 📝 Hard 631 design-excel-sum-formula 🔒 📝 Hard 632 smallest-range 📝 Hard 633 sum-of-square-numbers 📝 Easy 634 find-the-derangement-of-an-array 🔒 📝 Medium 635 design-log-storage-system 🔒 📝 Medium 636 exclusive-time-of-functions 📝 Medium 637 average-of-levels-in-binary-tree 📝 Easy 638 shopping-offers 📝 Medium 639 decode-ways-ii 📝 Hard 640 solve-the-equation 📝 Medium 642 design-search-autocomplete-system 🔒 📝 Hard 643 maximum-average-subarray-i 📝 Easy 644 maximum-average-subarray-ii 🔒 📝 Hard 645 set-mismatch 📝 Easy 646 maximum-length-of-pair-chain 📝 Medium 647 palindromic-substrings 📝 Medium 648 replace-words 📝 Medium 649 dota2-senate 📝 Medium 650 2-keys-keyboard 📝 Medium 651 4-keys-keyboard 🔒 📝 Medium 652 find-duplicate-subtrees 📝 Medium 653 two-sum-iv-input-is-a-bst 📝 Easy 654 maximum-binary-tree 📝 Medium 655 print-binary-tree 📝 Medium 656 coin-path 🔒 📝 Hard 657 robot-return-to-origin 📝 Easy 658 find-k-closest-elements 📝 Medium 659 split-array-into-consecutive-subsequences 📝 Medium 660 remove-9 🔒 📝 Hard 661 image-smoother 📝 Easy 662 maximum-width-of-binary-tree 📝 Medium 663 equal-tree-partition 🔒 📝 Medium 664 strange-printer 📝 Hard 665 non-decreasing-array 📝 Easy 666 path-sum-iv 🔒 📝 Medium 667 beautiful-arrangement-ii 📝 Medium 668 kth-smallest-number-in-multiplication-table 📝 Hard 669 trim-a-binary-search-tree 📝 Easy 670 maximum-swap 📝 Medium 671 second-minimum-node-in-a-binary-tree 📝 Easy 672 bulb-switcher-ii 📝 Medium 673 number-of-longest-increasing-subsequence 📝 Medium 674 longest-continuous-increasing-subsequence 📝 Easy 675 cut-off-trees-for-golf-event 📝 Hard 676 implement-magic-dictionary 📝 Medium 677 map-sum-pairs 📝 Medium 678 valid-parenthesis-string 📝 Medium 679 24-game 📝 Hard 680 valid-palindrome-ii 📝 Easy 681 next-closest-time 🔒 📝 Medium 682 baseball-game 📝 Easy 683 k-empty-slots 🔒 📝 Hard 684 redundant-connection 📝 Medium 685 redundant-connection-ii 📝 Hard 686 repeated-string-match 📝 Easy 687 longest-univalue-path 📝 Easy 688 knight-probability-in-chessboard 📝 Medium 689 maximum-sum-of-3-non-overlapping-subarrays 📝 Hard 690 employee-importance 📝 Easy 691 stickers-to-spell-word 📝 Hard 692 top-k-frequent-words 📝 Medium 693 binary-number-with-alternating-bits 📝 Easy 694 number-of-distinct-islands 🔒 📝 Medium 695 max-area-of-island 📝 Easy 696 count-binary-substrings 📝 Easy 697 degree-of-an-array 📝 Easy 698 partition-to-k-equal-sum-subsets 📝 Medium 699 falling-squares 📝 Hard 711 number-of-distinct-islands-ii 🔒 📝 Hard 712 minimum-ascii-delete-sum-for-two-strings 📝 Medium 713 subarray-product-less-than-k 📝 Medium 714 best-time-to-buy-and-sell-stock-with-transaction-fee 📝 Medium 715 range-module 📝 Hard 716 max-stack 🔒 📝 Hard 717 1-bit-and-2-bit-characters 📝 Easy 718 maximum-length-of-repeated-subarray 📝 Medium 719 find-k-th-smallest-pair-distance 📝 Hard 720 longest-word-in-dictionary 📝 Easy 721 accounts-merge 📝 Medium 722 remove-comments 📝 Medium 723 candy-crush 🔒 📝 Medium 724 find-pivot-index 📝 Easy 725 split-linked-list-in-parts 📝 Medium 726 number-of-atoms 📝 Hard 727 minimum-window-subsequence 🔒 📝 Hard 728 self-dividing-numbers 📝 Easy 729 my-calendar-i 📝 Medium 730 count-different-palindromic-subsequences 📝 Hard 731 my-calendar-ii 📝 Medium 732 my-calendar-iii 📝 Hard 733 flood-fill 📝 Easy 734 sentence-similarity 🔒 📝 Easy 735 asteroid-collision 📝 Medium 736 parse-lisp-expression 📝 Hard 737 sentence-similarity-ii 🔒 📝 Medium 738 monotone-increasing-digits 📝 Medium 739 daily-temperatures 📝 Medium 740 delete-and-earn 📝 Medium 741 cherry-pickup 📝 Hard 742 to-lower-case Easy 743 closest-leaf-in-a-binary-tree 🔒 📝 Medium 744 network-delay-time 📝 Medium 745 find-smallest-letter-greater-than-target 📝 Easy 746 prefix-and-suffix-search 📝 Hard 747 min-cost-climbing-stairs 📝 Easy 748 largest-number-at-least-twice-of-others 📝 Easy 749 shortest-completing-word 📝 Medium 750 contain-virus 📝 Hard 751 number-of-corner-rectangles 🔒 📝 Medium 752 ip-to-cidr 🔒 📝 Easy 753 open-the-lock 📝 Medium 754 cracking-the-safe 📝 Hard 755 reach-a-number 📝 Medium 756 pour-water 🔒 📝 Medium 757 pyramid-transition-matrix 📝 Medium 758 convert-binary-search-tree-to-sorted-doubly-linked-list 🔒 Medium 759 set-intersection-size-at-least-two 📝 Hard 760 bold-words-in-string 🔒 📝 Easy 761 employee-free-time 🔒 📝 Hard 762 find-anagram-mappings 🔒 📝 Easy 763 special-binary-string 📝 Hard 764 n-ary-tree-level-order-traversal Easy 765 serialize-and-deserialize-n-ary-tree 🔒 Hard 766 flatten-a-multilevel-doubly-linked-list Medium 767 prime-number-of-set-bits-in-binary-representation 📝 Easy 768 partition-labels 📝 Medium 769 largest-plus-sign 📝 Medium 770 couples-holding-hands 📝 Hard 771 encode-n-ary-tree-to-binary-tree 🔒 Hard 772 construct-quad-tree Easy 773 quad-tree-intersection Easy 774 maximum-depth-of-n-ary-tree Easy 775 n-ary-tree-preorder-traversal Easy 776 n-ary-tree-postorder-traversal Easy 777 toeplitz-matrix 📝 Easy 778 reorganize-string 📝 Medium 779 max-chunks-to-make-sorted-ii 📝 Hard 780 max-chunks-to-make-sorted 📝 Medium 781 basic-calculator-iv 📝 Hard 782 jewels-and-stones 📝 Easy 783 search-in-a-binary-search-tree Easy 784 insert-into-a-binary-search-tree Medium 785 basic-calculator-iii 🔒 Hard 786 search-in-a-sorted-array-of-unknown-size 🔒 Medium 787 sliding-puzzle 📝 Hard 788 minimize-max-distance-to-gas-station 🔒 📝 Hard 789 kth-largest-element-in-a-stream Easy 790 global-and-local-inversions 📝 Medium 791 split-bst 🔒 📝 Medium 792 binary-search Easy 793 swap-adjacent-in-lr-string 📝 Medium 794 swim-in-rising-water 📝 Hard 795 k-th-symbol-in-grammar 📝 Medium 796 reaching-points 📝 Hard 797 rabbits-in-forest 📝 Medium 798 transform-to-chessboard 📝 Hard 799 minimum-distance-between-bst-nodes 📝 Easy 800 letter-case-permutation 📝 Easy 801 is-graph-bipartite 📝 Medium 802 k-th-smallest-prime-fraction 📝 Hard 803 cheapest-flights-within-k-stops 📝 Medium 804 rotated-digits 📝 Easy 805 escape-the-ghosts 📝 Medium 806 domino-and-tromino-tiling 📝 Medium 807 custom-sort-string 📝 Medium 808 number-of-matching-subsequences 📝 Medium 809 preimage-size-of-factorial-zeroes-function 📝 Hard 810 valid-tic-tac-toe-state 📝 Medium 811 number-of-subarrays-with-bounded-maximum 📝 Medium 812 rotate-string 📝 Easy 813 all-paths-from-source-to-target 📝 Medium 814 smallest-rotation-with-highest-score 📝 Hard 815 champagne-tower 📝 Medium 816 design-hashset Easy 817 design-hashmap Easy 818 similar-rgb-color 🔒 📝 Easy 819 minimum-swaps-to-make-sequences-increasing 📝 Medium 820 find-eventual-safe-states 📝 Medium 821 bricks-falling-when-hit 📝 Hard 822 unique-morse-code-words 📝 Easy 823 split-array-with-same-average 📝 Hard 824 number-of-lines-to-write-string 📝 Easy 825 max-increase-to-keep-city-skyline 📝 Medium 826 soup-servings 📝 Medium 827 expressive-words 📝 Medium 828 chalkboard-xor-game 📝 Hard 829 subdomain-visit-count 📝 Easy 830 largest-triangle-area 📝 Easy 831 largest-sum-of-averages 📝 Medium 832 binary-tree-pruning 📝 Medium 833 bus-routes 📝 Hard 834 ambiguous-coordinates 📝 Medium 835 linked-list-components 📝 Medium 836 race-car 📝 Hard 837 most-common-word 📝 Easy 838 design-linked-list Easy 839 short-encoding-of-words 📝 Medium 841 shortest-distance-to-a-character 📝 Easy 842 card-flipping-game 📝 Medium 843 binary-trees-with-factors 📝 Medium 850 insert-into-a-cyclic-sorted-list 🔒 Medium 851 goat-latin 📝 Easy 852 friends-of-appropriate-ages 📝 Medium 853 most-profit-assigning-work 📝 Medium 854 making-a-large-island 📝 Hard 855 unique-letter-string 📝 Hard 856 consecutive-numbers-sum 📝 Medium 857 positions-of-large-groups 📝 Easy 858 masking-personal-information 📝 Medium 859 design-circular-deque Medium 860 design-circular-queue Medium 861 flipping-an-image 📝 Easy 862 find-and-replace-in-string 📝 Medium 863 sum-of-distances-in-tree 📝 Hard 864 image-overlap 📝 Medium 865 robot-room-cleaner 🔒 Hard 866 rectangle-overlap 📝 Easy 867 new-21-game 📝 Medium 868 push-dominoes 📝 Medium 869 similar-string-groups 📝 Hard 870 magic-squares-in-grid 📝 Easy 871 keys-and-rooms 📝 Medium 872 split-array-into-fibonacci-sequence 📝 Medium 873 guess-the-word 📝 Hard 874 backspace-string-compare 📝 Easy 875 longest-mountain-in-array 📝 Medium 876 hand-of-straights 📝 Medium 877 shortest-path-visiting-all-nodes 📝 Hard 878 shifting-letters 📝 Medium 879 maximize-distance-to-closest-person 📝 Easy 880 rectangle-area-ii 📝 Hard 881 loud-and-rich 📝 Medium 882 peak-index-in-a-mountain-array 📝 Easy 883 car-fleet 📝 Medium 884 k-similar-strings 📝 Hard 885 exam-room 📝 Medium 886 score-of-parentheses 📝 Medium 887 minimum-cost-to-hire-k-workers 📝 Hard 888 mirror-reflection 📝 Medium 889 buddy-strings 📝 Easy 890 lemonade-change 📝 Easy 891 score-after-flipping-matrix 📝 Medium 892 shortest-subarray-with-sum-at-least-k 📝 Hard 893 all-nodes-distance-k-in-binary-tree 📝 Medium 894 random-pick-with-blacklist 📝 Hard 895 shortest-path-to-get-all-keys 📝 Hard 896 smallest-subtree-with-all-the-deepest-nodes 📝 Medium 897 prime-palindrome 📝 Medium 898 transpose-matrix 📝 Easy 899 binary-gap 📝 Easy 900 reordered-power-of-2 📝 Medium 901 advantage-shuffle 📝 Medium 902 minimum-number-of-refueling-stops 📝 Hard 903 implement-rand10-using-rand7 📝 Medium 904 leaf-similar-trees 📝 Easy 905 length-of-longest-fibonacci-subsequence 📝 Medium 906 walking-robot-simulation 📝 Easy 907 koko-eating-bananas 📝 Medium 908 middle-of-the-linked-list 📝 Easy 909 stone-game 📝 Medium 910 nth-magical-number 📝 Hard 911 profitable-schemes 📝 Hard 912 random-pick-with-weight 📝 Medium 913 random-flip-matrix 📝 Medium 914 random-point-in-non-overlapping-rectangles 📝 Medium 915 generate-random-point-in-a-circle 📝 Medium 916 decoded-string-at-index 📝 Medium 917 boats-to-save-people 📝 Medium 918 reachable-nodes-in-subdivided-graph 📝 Hard 919 projection-area-of-3d-shapes 📝 Easy 920 uncommon-words-from-two-sentences 📝 Easy 921 spiral-matrix-iii 📝 Medium 922 possible-bipartition 📝 Medium 923 super-egg-drop 📝 Hard 924 fair-candy-swap 📝 Easy 925 construct-binary-tree-from-preorder-and-postorder-traversal 📝 Medium 926 find-and-replace-pattern 📝 Medium 927 sum-of-subsequence-widths 📝 Hard 928 surface-area-of-3d-shapes 📝 Easy 929 groups-of-special-equivalent-strings 📝 Easy 930 all-possible-full-binary-trees 📝 Medium 931 maximum-frequency-stack 📝 Hard 932 monotonic-array 📝 Easy 933 increasing-order-search-tree 📝 Easy 934 bitwise-ors-of-subarrays 📝 Medium 935 orderly-queue 📝 Hard 936 rle-iterator 📝 Medium 937 online-stock-span 📝 Medium 938 numbers-at-most-n-given-digit-set 📝 Hard 939 valid-permutations-for-di-sequence 📝 Hard