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| # | Title | Solutions | Difficulty | Tag |
|---|---|---|---|---|
| 704 | binary-search | Solution | Easy | Array, Binary Search |
| 278 | first-bad-version | Solution | Easy | Binary Search |
| 35 | search-insert-position | Solution | Easy | Array, Binary Search |
| 977 | squares-of-a-sorted-array | Solution | Easy | Array, Two Pointers, Sort |
| 189 | rotate-array | Solution | Medium | Array, Two Pointers, Math |
| 283 | move-zeroes | Solution | Easy | Array, Two Pointers |
| 167 | two-sum-ii-input-array-is-sorted | Solution | Easy | Array, Two Pointers, Binary Search |
| 344 | reverse-string | Solution | Easy | Recursion, Two Pointers, String |
| 557 | reverse-words-in-a-string-iii | Solution | Easy | Two Pointers, String |
| 876 | middle-of-the-linked-list | Solution | Easy | LinkedList, Two Pointers |
| 19 | remove-nth-node-from-end-of-list | Solution | Medium | LinkedList, Two Pointers |
| 3 | longest-substring-without-repeating-characters | Solution | Medium | HashTable, String, Sliding Window |
| 567 | permutation-in-string | Solution | Medium | HashTable, Two Pointers, String |
| 733 | flood-fill | Solution | Easy | DFS, BFS, Array |
| 695 | max-area-of-island | Solution | Medium | DFS, BFS |
| 617 | merge-two-binary-trees | Solution | Easy | Tree, DFS, BFS |
| 116 | populating-next-right-pointers-in-each-node | Solution | Medium | Tree, DFS, BFS |
| 542 | 01-matrix | Solution | Medium | BFS, Array, Dynamic Programming |
| 994 | rotting-oranges | Solution | Medium | BFS, Array, Matrix |
| 21 | merge-two-sorted-lists | Solution | Easy | Recursion, LinkedList |
| 206 | reverse-linked-list | Solution | Easy | Recursion, LinkedList |
| 77 | combinations | Solution | Medium | Array, Backtracking |
| 46 | permutations | Solution | Medium | Array, Backtracking |
| 784 | letter-case-permutation | Solution | Medium | Bit Manipulation, String, Backtracking |
| 70 | climbing-stairs | Solution | Easy | Memory Search, Math, Dynamic Programming |
| 198 | house-robber | Solution | Medium | Array, Dynamic Programming |
| 120 | triangle | Solution | Medium | Array, Dynamic Programming |
| 231 | power-of-two | Solution | Easy | Bit Manipulation, Recursion, Math |
| 191 | number-of-1-bits | Solution | Easy | Bit Manipulation |
| 190 | reverse-bits | Solution | Easy | Bit Manipulation, Divide and Conquer |
| 136 | single-number | Solution | Easy | Bit Manipulation, Array |
| 34 | find-first-and-last-position-of-element-in-sorted-array | Solution | Medium | Array, Binary Search |
| 153 | find-minimum-in-rotated-sorted-array | Solution | Medium | Array, Binary Search |
| 33 | search-in-rotated-sorted-array | Solution | Medium | Array, Binary Search |
| 82 | remove-duplicates-from-sorted-list-ii | Solution | Medium | LinkedList, Two Pointers |
| 844 | backspace-string-compare | Solution | Easy | Stack, Two Pointers, String, Simulation |
| 986 | interval-list-intersections | Solution | Medium | Array, Two Pointers |
| 438 | find-all-anagrams-in-a-string | Solution | Medium | Hash Table, String, Sliding Window |
| 713 | subarray-product-less-than-k | Solution | Medium | Array, Sliding Window |
| 200 | number-of-islands | Solution | Medium | DFS, BFS |
| 117 | populating-next-right-pointers-in-each-node-ii | Solution | Medium | Tree, DFS, BFS |
| 1091 | shortest-path-in-binary-matrix | Solution | Medium | BFS, Array, Matrix |
| 78 | subsets | Solution | Medium | Bit Manipulation, Array, Backtracking |
| 47 | permutations-ii | Solution | Medium | Array, Backtracking |
| 17 | letter-combinations-of-a-phone-number | Solution | Medium | Hash Table, String, Backtracking |
| 213 | house-robber-ii | Solution | Medium | Array, Dynamic Programming |
| 45 | jump-game-ii | Solution | Medium | Greedy, Array, Dynamic Programming |
| 5 | longest-palindromic-substring | Solution | Medium | String, Dynamic Programming |
| 91 | decode-ways | Solution | Medium | String, Dynamic Programming |
| 300 | longest-increasing-subsequence | Solution | Medium | Array, Binary Search, Dynamic Programming |
| 1143 | longest-common-subsequence | Solution | Medium | String, Dynamic Programming |
| 322 | coin-change | Solution | Medium | BFS, Array, Dynamic Programming |
| 201 | bitwise-and-of-numbers-range | Solution | Medium | Bit Manipulation |
| 384 | shuffle-an-array | Solution | Medium | Array, Math, Randomized |
| 130 | surrounded-regions | Solution | Medium | Array, Math, Randomized |
| 74 | search-a-2d-matrix | Solution | Medium | Array, Binary Search, Matrix |
| 162 | find-peak-element | Solution | Medium | Array, Binary Search |
| 15 | 3sum | Solution | Medium | Array, Two Pointers, Sorting |
| 11 | container-with-most-water | Solution | Medium | Greedy, Array, Two Pointers |
| 209 | minimum-size-subarray-sum | Solution | Medium | Array, Binary Search, Prefix Sum |
| 547 | number-of-provinces | Solution | Medium | DFS, BFS |
| 572 | subtree-of-another-tree | Solution | Easy | Tree, DFS, Binary Tree |
| 797 | all-paths-from-source-to-target | Solution | Medium | DFS, BFS, Graph |
| 90 | subsets-ii | Solution | Medium | Bit Manipulation, Array, Backtracking |
| 39 | combination-sum | Solution | Medium | Array, Backtracking |
| 22 | generate-parentheses | Solution | Medium | String, Dynamic Programming, Backtracking |
| 55 | jump-game | Solution | Medium | Greedy, Array, Dynamic Programming |
| 62 | unique-paths | Solution | Medium | Math, Dynamic Programming, Combinatorics |
| 40 | combination-sum-ii | Solution | Medium | Array, Backtracking |
| 413 | arithmetic-slices | Solution | Medium | Array, Backtracking |
| 79 | word-search | Solution | Medium | Array, Backtracking, Matrix |
| 139 | word-break | Solution | Medium | Trie, Memoization, Array, Hash Table |
| 673 | number-of-longest-increasing-subsequence | Solution | Medium | Binary Indexed Tree, Segment Tree, Array |
| 583 | delete-operation-for-two-strings | Solution | Medium | String, Dynamic Programming |
| 343 | integer-break | Solution | Medium | Math, Dynamic Programming |
| 72 | edit-distance | Solution | Hard | String, Dynamic Programming |
| 202 | happy-number | Solution | Easy | Hash Table, Math, Two Pointers |
| 149 | max-points-on-a-line | Solution | Hard | Geometry, Hash Table, Math |
| 217 | contains-duplicate | Solution | Easy | Array, Hash Table, Sorting |
| 1 | two-sum | Solution | Easy | Array, Hash Table |
| 350 | intersection-of-two-arrays-ii | Solution | Easy | Array, Hash Table, Two Pointers, Binary Search |
| 566 | reshape-the-matrix | Solution | Easy | Array, Matrix, Simulation |
| 36 | valid-sudoku | Solution | Medium | Array, Hash Table, Matrix |
| 387 | first-unique-character-in-a-string | Solution | Easy | Queue, Hash Table, String, Counting |
| 141 | linked-list-cycle | Solution | Easy | Hash Table, LinkedList, Two Pointers |
| 83 | remove-duplicates-from-sorted-list | Solution | Easy | Hash Table |
| 20 | valid-parentheses | Solution | Easy | Stack, String |
| 144 | binary-tree-preorder-traversal | Solution | Easy | Stack, Tree, DFS, Binary Tree |
| 104 | maximum-depth-of-binary-tree | Solution | Easy | Tree, DFS, BFS |
| 101 | symmetric-tree | Solution | Easy | Tree, DFS, BFS |
| 226 | invert-binary-tree | Solution | Easy | Tree, DFS, BFS |
| 700 | search-in-a-binary-search-tree | Solution | Easy | Tree, Binary Search Tree, Binary Tree |
| 383 | ransom-note | Solution | Easy | Hash Table, String, Counting |
| 94 | binary-tree-inorder-traversal | Solution | Easy | Stack, Tree, DFS, Binary Tree |
| 53 | maximum-subarray | Solution | Easy | Array, Divide And Conquer, Dynamic Programming |
| 88 | merge-sorted-array | Solution | Easy | Array, Two Pointers, Sorting |
| 121 | best-time-to-buy-and-sell-stock | Solution | Easy | Array, Dynamic Programming |
| 118 | pascals-triangle | Solution | Easy | Array, Dynamic Programming |
| 73 | set-matrix-zeroes | Solution | Medium | Array, Hash Table, Matrix |
| 242 | valid-anagram | Solution | Easy | Hash Table, String, Sorting |
| 203 | remove-linked-list-elements | Solution | Easy | Recursion, LinkedList |
| 232 | implement-queue-using-stacks | Solution | Easy | Stack, Design, Queue |
| 145 | binary-tree-postorder-traversal | Solution | Easy | Stack, Tree, DFS, Binary Tree |
| 102 | binary-tree-level-order-traversal | Solution | Medium | Tree, BFS, Binary Tree |
| 112 | path-sum | Solution | Easy | Tree, DFS, Binary Tree |
| 701 | insert-into-a-binary-search-tree | Solution | Medium | Tree, Binary Search Tree, Binary Tree |
| 653 | two-sum-iv-input-is-a-bst | Solution | Easy | Tree, DFS, BFS |
| 235 | lowest-common-ancestor-of-a-binary-search-tree | Solution | Easy | Tree, DFS, BFS |
| 98 | validate-binary-search-tree | Solution | Medium | Tree, DFS, BFS, Binary Search Tree |
| 169 | majority-element | Solution | Easy | Array, Hash Table, Divide and Conquer, Counting |
| 75 | sort-colors | Solution | Medium | Array, Two Pointers, Sorting |
| 119 | pascals-triangle-ii | Solution | Easy | Array, Dynamic Programming |
| 240 | search-a-2d-matrix-ii | Solution | Medium | Array, Binary Search, Divide and Conquer, Matrix |
| 238 | product-of-array-except-self | Solution | Medium | Array, Prefix Sum |
| 415 | add-strings | Solution | Easy | Math, String, Simulation |
| 290 | word-pattern | Solution | Easy | Hash Table, String |
| 43 | multiply-strings | Solution | Medium | Math, String, Simulation |
| 706 | design-hashmap | Solution | Easy | Design, Array, Hash Table, Linked List |
| 2 | add-two-numbers | Solution | Medium | Recursion, Linked List, Math |
| 160 | intersection-of-two-linked-lists | Solution | Easy | Hash Table, Linked List, Two Pointers |
| 707 | design-linked-list | Solution | Medium | Design, Linked List |
| 143 | reorder-list | Solution | Medium | Stack, Recursion, Linked List, Two Pointers |
| 155 | min-stack | Solution | Easy | Stack, Design |
| 108 | convert-sorted-array-to-binary-search-tree | Solution | Easy | Tree, Binary Search Tree, Array, Divide and Conquer |
| 113 | path-sum-ii | Solution | Medium | Tree, DFS, Backtracking, Binary Tree |
| 230 | kth-smallest-element-in-a-bst | Solution | Medium | Tree, DFS, Binary Search Tree |
| 236 | lowest-common-ancestor-of-a-binary-tree | Solution | Medium | Tree, DFS, Binary Tree |
| 997 | find-the-town-judge | Solution | Easy | Graph, Array, Hash Table |
| 215 | kth-largest-element-in-an-array | Solution | Medium | Array, Divide and Conquer, Quickselect, Sorting |
| 164 | maximum-gap | Solution | Hard | Array, Bucket Sort, Radix Sort, Sorting |
| 56 | merge-intervals | Solution | Medium | Array, Bucket Sorting |
| 48 | rotate-image | Solution | Medium | Array, Math, Matrix |
| 59 | spiral-matrix-ii | Solution | Medium | Array, Math, Matrix |
| 435 | non-overlapping-intervals | Solution | Medium | Greedy, Array, Dynamic Programming, Sorting |
| 334 | increasing-triplet-subsequence | Solution | Medium | Greedy, Array |
| 409 | longest-palindrome | Solution | Easy | Greedy, Hash Table, String |
| 763 | partition-labels | Solution | Medium | Greedy, Hash Table, Two Pointers, String |
| 49 | group-anagrams | Solution | Medium | Hash Table, String, Sorting |
| 560 | subarray-sum-equals-k | Solution | Medium | Array, Hash Table, Prefix Sum |
| 187 | repeated-dna-sequences | Solution | Medium | Bit Manipulation, Hash Table, String |
| 142 | linked-list-cycle-ii | Solution | Medium | Hash Table, Linked List, Two Pointers |
| 1249 | minimum-remove-to-make-valid-parentheses | Solution | Medium | Stack, String |
| 24 | swap-nodes-in-pairs | Solution | Medium | Recursion, Linked List |
| 1823 | find-the-winner-of-the-circular-game | Solution | Medium | Recursion, Array, Math, Simulation |
| 105 | construct-binary-tree-from-preorder-and-inorder-traversal | Solution | Medium | Tree, Array, Hash Table, Divide and Conquer |
| 199 | binary-tree-right-side-view | Solution | Medium | Tree, DFS, BFS |
| 25 | reverse-nodes-in-k-group | Solution | Hard | Recursion, Linked List |
| 173 | binary-search-tree-iterator | Solution | Medium | Stack, Tree, Design, Binary Search Tree |
| 297 | serialize-and-deserialize-binary-tree | Solution | Hard | Tree, DFS, BFS |
| 103 | binary-tree-zigzag-level-order-traversal | Solution | Medium | Tree, BFS, Binary Tree |
| 1557 | minimum-number-of-vertices-to-reach-all-nodes | Solution | Medium | Graph |
| 451 | sort-characters-by-frequency | Solution | Medium | Hash Table, String, Bucket Sort, Counting |
| 973 | k-closest-points-to-origin | Solution | Medium | Hash Table, String, Bucket Sort, Counting |
| 347 | top-k-frequent-elements | Solution | Medium | Array, Hash Table, Divide and Conquer, Bucket Sort |
| 841 | keys-and-rooms | Solution | Medium | DFS, BFS, Graph |
| 509 | fibonacci-number | Solution | Easy | Recursion, Memoization, Math |
| 746 | min-cost-climbing-stairs | Solution | Easy | Array, Dynamic Programming |
| 918 | maximum-sum-circular-subarray | Solution | Medium | Queue, Array, Divide and Conquer, Dynamic Programming |
| 152 | maximum-product-subarray | Solution | Medium | Array, Dynamic Programming |
| 1014 | best-sightseeing-pair | Solution | Medium | Array, Dynamic Programming |
| 309 | best-time-to-buy-and-sell-stock-with-cooldown | Solution | Medium | Array, Dynamic Programming |
| 450 | delete-node-in-a-bst | Solution | Medium | Tree, Binary Search Tree, Binary Tree |
| 264 | ugly-number-ii | Solution | Medium | Hash Table, Math, Dynamic Programming |
| 931 | minimum-falling-path-sum | Solution | Medium | Array, Dynamic Programming, Matrix |
| 64 | minimum-path-sum | Solution | Medium | Array, Dynamic Programming, Matrix |
| 1314 | matrix-block-sum | Solution | Medium | Array, Matrix, Prefix Sum |
| 392 | is-subsequence | Solution | Easy | Two Pointers, String, Dynamic Programming |
| 42 | trapping-rain-water | Solution | Hard | Stack, Array, Two Pointers, Dynamic Programming |
| 377 | combination-sum-iv | Solution | Medium | Array, Dynamic Programming |
| 1137 | n-th-tribonacci-number | Solution | Easy | Memoization, Math, Dynamic Programming |
| 740 | delete-and-earn | Solution | Medium | Array, Hash Table, Dynamic Programming |
| 1567 | maximum-length-of-subarray-with-positive-product | Solution | Medium | Greedy, Array, Dynamic Programming |
| 122 | best-time-to-buy-and-sell-stock-ii | Solution | Medium | Greedy, Array, Dynamic Programming |
| 714 | best-time-to-buy-and-sell-stock-with-transaction-fee | Solution | Medium | Greedy, Array, Dynamic Programming |
| 96 | unique-binary-search-trees | Solution | Medium | Tree, Binary Search Tree, Math, Dynamic Programming |
| 304 | range-sum-query-2d-immutable | Solution | Medium | Design, Array, Matrix, Prefix Sum |
| 63 | unique-paths-ii | Solution | Medium | Array, Dynamic Programming, Matrix |
| 221 | maximal-square | Solution | Medium | Array, Dynamic Programming, Matrix |
| 516 | longest-palindromic-subsequence | Solution | Medium | String, Dynamic Programming |
| 518 | coin-change-2 | Solution | Medium | Array, Dynamic Programming |
| 9 | palindrome-number | Python,Go | Easy | Math |
| 13 | roman-to-integer | Python,Go | Easy | Hash Table, Math, String |
| 14 | longest-common-prefix | Python,Go | Easy | String |
| 26 | remove-duplicates-from-sorted-array | Python,Go | Easy | Array, Two Pointers |
| 27 | remove-element | Python,Go | Easy | Array, Two Pointers |
| 28 | implement-strstr | Python,Go | Easy | Two Pointers, String, String Matching |
| 58 | length-of-last-word | Python,Go | Easy | String |
| 66 | plus-one | Python,Go | Easy | Array, Math |
| 67 | add-binary | Python,Go | Easy | Bit Manipulation, Math, String, Simulation |
| 69 | sqrtx | Python,Go | Easy | Math, Binary Search |
| 100 | same-tree | Python,Go | Easy | Tree, DFS, BFS, Binary Tree |
| 110 | balanced-binary-tree | Python,Go | Easy | Tree, DFS, Binary Tree |
| 111 | minimum-depth-of-binary-tree | Python,Go | Easy | Tree, DFS, BFS, Binary Tree |
| 125 | valid-palindrome | Python,Go | Easy | Two Pointers, String |
| 168 | excel-sheet-column-title | Python,Go | Easy | Math, String |
| 171 | excel-sheet-column-number | Python,Go | Easy | Math, String |
| 175 | combine-two-tables | SQL | Easy | Database |
| 205 | isomorphic-strings | Python,Go | Easy | Hash Table, String |
| 219 | contains-duplicate-ii | Python,Go | Easy | Array, Hash Table, Sliding Window |
| 225 | implement-stack-using-queues | Python,Go | Easy | Stack, Design, Queue |
| 228 | summary-ranges | Python,Go | Easy | Array |
| 234 | palindrome-linked-list | Python,Go | Easy | Stack, Recursion, Linked List, Two Pointers |
| 237 | delete-node-in-a-linked-list | Python,Go | Easy | Linked List |
| 257 | binary-tree-paths | Python,Go | Easy | Tree, DFS, String, Backtracking, Binary Tree |
| 258 | add-digits | Python,Go | Easy | Match, Number Theory, Simulation |
| 263 | ugly-number | Python,Go | Easy | Math |
| 268 | missing-number | Python,Go | Easy | Bit Manipulation, Array, Hash Table, Math, Sorting |
| 292 | nim-game | Python,Go | Easy | Brainteaser, Math, Game Theory |
| 303 | range-sum-query-immutable | Python,Go | Easy | Design, Array, Prefix Sum |
| 326 | power-of-three | Python,Go | Easy | Recursion, Math |
| 338 | counting-bits | Python,Go | Easy | Bit Manipulation, Dynamic Programming |
| 342 | power-of-four | Python,Go | Easy | Bit Manipulation, Recursion, Math |
| 345 | reverse-vowels-of-a-string | Python,Go | Easy | Two Pointers, String |
| 349 | intersection-of-two-arrays | Python,Go | Easy | Array, Hash Table, Two Pointers, Binary Search, Sorting |
| 367 | valid-perfect-square | Python,Go | Easy | Math, Binary Search |
| 374 | guess-number-higher-or-lower | Python,Go | Easy | Binary Search, interactive |
| 389 | find-the-difference | Python,Go | Easy | Bit Manipulation, Hash Table, String, Sorting |
| 401 | binary-watch | Python,Go | Easy | Bit Manipulation, Backtracking |
| 404 | sum-of-left-leaves | Python,Go | Easy | Tree, DFS, BFS, Binary Tree |
| 405 | convert-a-number-to-hexadecimal | Python,Go | Easy | Bit Manipulation, Math |
| 412 | fizz-buzz | Python, Go | Easy | Math, String, Simulation |
| 414 | third-maximum-number | Python,Go | Easy | Array, Sorting |
| 434 | number-of-segments-in-a-string | Python,Go | Easy | String |
| 441 | arranging-coins | Python, Go | Easy | Math, Binary Search |
| 448 | find-all-numbers-disappeared-in-an-array | Python,Go | Easy | Array, Hash Table |
| 453 | minimum-moves-to-equal-array-elements | Python,Go | Easy | Array, Math |
| 455 | assign-cookies | Python,Go | Easy | Greedy, Array, Sorting |
| 459 | repeated-substring-pattern | Python,Go | Easy | String, String Matching |
| 461 | hamming-distance | Python,Go | Easy | Bit Manipulation |
| 463 | island-perimeter | Python,Go | Easy | DFS, BFS, Array, Matrix |
| 476 | number-complement | Python,Go | Easy | Bit Manipulation |
| 482 | license-key-formatting | Python,Go | Easy | String |
| 485 | max-consecutive-ones | Python,Go | Easy | Array |
| 496 | next-greater-element-i | Python,Go | Easy | Stack, Array, Hash Table, Monotonic Stack |
| 492 | construct-the-rectangle | Python,Go | Easy | Math |
| 495 | teemo-attacking | Python,Go | Easy | Array, Simulation |
| 500 | keyboard-row | Go | Easy | Array, Hash Table, String |
| 501 | find-mode-in-binary-search-tree | Python,Go | Easy | Tree, DFS, Binary Search Tree, Binary Tree |
