Coding Interview Problems
| DIFFICULTY | PROBLEM | ONLINE JUDGES | SOLUTIONS |
|---|---|---|---|
Medium | 3sum-closest | LeetCode 16 | Java |
Medium | 3sum | LeetCode 15 | Java |
Medium | 4sum | LeetCode 18 | Java |
Easy | add-binary | LeetCode 67 | Java |
Easy | add-digits | LeetCode 258 | Java |
Medium | add-two-numbers | LeetCode 258 | Java |
Medium | anagrams | LintCode 171 | Java |
Medium | backpack-ii | LintCode 125 | Java |
Medium | backpack | LintCode 92 | Java |
Easy | balanced-binary-tree | LeetCode 110 | Java |
balanced-lineup | POJ 3264 | Java | |
Medium | best-time-to-buy-and-sell-stock-ii | LeetCode 122 | Java |
Medium | best-time-to-buy-and-sell-stock-iii | LeetCode 123 | Java |
Easy | best-time-to-buy-and-sell-stock | LeetCode 121 | Java |
Hard | binary-representation | LintCode 180 | Java |
Medium | binary-search-tree-iterator | LeetCode 173 | Java |
Easy | binary-tree-inorder-traversal | LeetCode 94 | Java Python |
Medium | binary-tree-level-order-traversal-ii | LeetCode 107 | Java |
Medium | binary-tree-level-order-traversal | LeetCode 102 | Java |
Hard | binary-tree-maximum-path-sum | LeetCode 124 | Java |
Easy | binary-tree-path-sum | LintCode 1358 | Java |
Easy | binary-tree-paths | LeetCode 257 | Java |
Easy | binary-tree-postorder-traversal | LeetCode 145 | Java Python |
Easy | binary-tree-preorder-traversal | LeetCode 144 | Java Python |
Medium | binary-tree-zigzag-level-order-traversal | LeetCode 103 LintCode 71 | Java |
Hard | candy | LeetCode 135 | Java |
Easy | climbing-stairs | LeetCode 70 | Java |
Medium | clone-binary-tree | LintCode 375 | Java |
Medium | clone-graph | LeetCode 133 | Java |
Medium | coins-in-a-line | LintCode 394 | Java |
Medium | combination-sum-ii | LeetCode 377 LintCode 564 | Java |
Medium | combination-sum-iv | LeetCode 40 | Java |
Medium | combination-sum | LeetCode 39 | Java |
Medium | combinations | LintCode 152 | Java |
Easy | compare-strings | LintCode 55 | Java |
Medium | construct-binary-tree-from-inorder-and-postorder-traversal | LeetCode 106 | Java |
Medium | construct-binary-tree-from-preorder-and-inorder-traversal | LeetCode 105 | Java |
Medium | container-with-most-water | LeetCode 11 | Java |
Medium | continuous-subarray-sum | LeetCode 523 | Java |
Medium | convert-binary-search-tree-to-sorted-doubly-linked-list | LeetCode 426 LintCode 1534 | Java |
Easy | convert-sorted-array-to-binary-search-tree-with-minimal-height | LeetCode 108 | Java |
Medium | convert-sorted-list-to-balanced-bst | LeetCode 109 | Java |
Medium | copy-list-with-random-pointer | LeetCode 138 | Java |
Easy | cosine-similarity | LintCode 445 | Java |
Easy | count-1-in-binary | LintCode 365 | Java |
Easy | count-and-say | LeetCode 38 LintCode 420 | Java |
data-stream-median | Java | ||
Medium | decode-ways | LeetCode 91 | Java |
Medium | delete-digits | LintCode 182 | Java |
Easy | delete-node-in-the-middle-of-singly-linked-list | LeetCode 237 LintCode 372 | Java |
Medium | design-add-and-search-words-data-structure | LeetCode 211 | Java |
Hard | distinct-subsequences | LeetCode 115 LintCode 118 | Java |
Hard | edit-distance | LeetCode 72 LintCode 119 | Java |
Medium | evaluate-reverse-polish-notation | LeetCode 150 LintCode 424 | Java |
Medium | fast-power | LintCode 140 | Java |
Easy | fibonacci | LintCode 366 | Java |
Hard | find-minimum-in-rotated-sorted-array-ii | LeetCode 154 LintCode 160 | Java |
Medium | find-minimum-in-rotated-sorted-array | LeetCode 153 LintCode 159 | Java |
Medium | find-peak-element | LeetCode 162 LintCode 75 | Java |
Medium | find-the-missing-number | LintCode 681 | Java |
Easy | first-bad-version | LeetCode 278 LintCode 74 | Java |
Hard | first-missing-positive | LeetCode 41 LintCode 189 | Java Go |
Easy | first-position-of-target | LintCode 14 | Java |
Easy | fizz-buzz | LeetCode 412 LintCode 9 | Java |
Medium | flatten-binary-tree-to-linked-list | LeetCode 114 LintCode 453 | Java |
Easy | flatten-list | LintCode 22 | Java |
Easy | flip-bits | LintCode 181 | Java |
Medium | gas-station | LeetCode 134 LintCode 187 | Java Go |
Medium | generate-parentheses | LeetCode 22 LintCode 427 | Java |
Medium | graph-valid-tree | LeetCode 261 LintCode 178 | Java |
Medium | gray-code | LeetCode 89 LintCode 411 | Java |
Easy | happy-number | LeetCode 202 LintCode 488 | Java |
Easy | hash-function | LintCode 128 | Java |
Medium | heapify | LintCode 130 | Java |
Medium | house-robber-ii | LeetCode 213 LintCode 534 | Java |
Medium | house-robber-iii | LeetCode 337 LintCode 535 | Java |
Medium | house-robber | LeetCode 198 LintCode 392 | Java |
Medium | implement-queue-by-two-stacks | LintCode 40 | Java |
Easy | implement-strstr | LeetCode 28 LintCode 13 | Java |
Medium | implement-trie-prefix-tree | LeetCode 208 LintCode 442 | Java |
Medium | insert-interval | LeetCode 57 LintCode 40 | Java |
Easy | insert-node-in-a-binary-search-tree | LintCode 85 | Java |
Medium | insertion-sort-list | LeetCode 147 LintCode 173 | Java Go |
Medium | integer-to-roman | LeetCode 12 LintCode 418 | Java |
Medium | interleaving-positive-and-negative-numbers | LintCode 144 | Java |
Medium | interleaving-string | LeetCode 97 LintCode 29 | Java |
Easy | intersection-of-two-arrays-ii | LeetCode 350 LintCode 548 | Java |
Easy | intersection-of-two-arrays | LeetCode 349 LintCode 547 | Java |
Easy | intersection-of-two-linked-lists | LeetCode 160 LintCode 380 | Java |
Medium | interval-minimum-number | LintCode 205 | Java |
Medium | interval-sum | LintCode 206 | Java |
Easy | invert-binary-tree | LeetCode 226 LintCode 175 | Java |
Medium | jump-game-ii | LeetCode 45 LintCode 117 | Java |
Medium | jump-game | LeetCode 55 LintCode 116 | Java |
Medium | kth-largest-element | LintCode 5 | Java |
Medium | kth-smallest-number-in-sorted-matrix | LintCode 401 | Java |
Medium | largest-number | LeetCode 179 LintCode 184 | Java |
Easy | left-pad | LintCode 524 | Java |
Easy | length-of-last-word | LeetCode 58 LintCode 422 | Java |
Medium | letter-combinations-of-a-phone-number | LeetCode 17 LintCode 425 | Java |
Medium | linked-list-cycle-ii | LeetCode 142 LintCode 103 | Java |
Easy | linked-list-cycle | LeetCode 141 LintCode 102 | Java |
Medium | lonely-integer | HackerRank | Java |
Easy | longest-common-prefix | LeetCode 14 LintCode 78 | Java |
Medium | longest-common-subsequence | LeetCode 1143 LintCode 77 | Java |
Medium | longest-common-substring | LintCode 79 | Java |
Medium | longest-consecutive-sequence | LeetCode 128 LintCode 124 | Java |
Easy | longest-increasing-continuous-subsequence | LintCode 397 | Java |
Medium | longest-increasing-subsequence | LeetCode 300 LintCode 76 | Java |
Medium | longest-palindromic-substring | LeetCode 5 LintCode 200 | Java |
Medium | longest-substring-without-repeating-characters | LeetCode 3 LintCode 384 | Java |
Easy | longest-words | LintCode 133 | Java |
Medium | lowest-common-ancestor-of-a-binary-tree | LeetCode 236 LintCode 88 | Java |
Hard | lru-cache | LeetCode 146 LintCode 134 | Java |
Easy | majority-number | LintCode 46 | Java |
Medium | majority-number-ii | LintCode 47 | Java |
Medium | majority-number-iii | LintCode 48 | Java |
Easy | matrix-zigzag-traversal | LintCode 185 | Java |
Hard | max-points-on-a-line | LeetCode 149 LintCode 186 | Java |
Easy | maximum-depth-of-binary-tree | LeetCode 104 LintCode 97 | Java |
Medium | maximum-product-subarray | LeetCode 152 LintCode 191s | Java |
Medium | maximum-subarray-difference | LintCode 45 | Java |
Medium | maximum-subarray-ii | LintCode 42 | Java |
Easy | maximum-subarray | LintCode 41 | Java |
Easy | median | LintCode 80 | Java |
Medium | merge-intervals | LeetCode 56 LintCode 156 | Java |
Hard | merge-k-sorted-lists | LeetCode 23 LintCode 104 | Java |
Easy | merge-sorted-array | LeetCode 88 | Java |
Easy | merge-two-sorted-arrays | LintCode 6 | Java Go |
Easy | merge-two-sorted-lists | LeetCode 21 LintCode 165 | Java |
Easy | min-stack | LeetCode 155 LintCode 12 | Java |
Medium | minimum-adjustment-cost | LintCode 91 | Java |
Easy | minimum-depth-of-binary-tree | LeetCode 111 LintCode 155 | Java |
Medium | minimum-path-sum | LeetCode 64 LintCode 110 | Java |
Medium | minimum-size-subarray-sum | LeetCode 209 LintCode 406 | Java |
Easy | minimum-subarray | LintCode 44 | Java |
Easy | mock-hanoi-tower-by-stacks | LintCode 227 | Java |
Easy | move-zeroes | LeetCode 283 LintCode 539 | Java |
Hard | n-queens-ii | LeetCode 52 LintCode 34 | Java |
Hard | n-queens | LeetCode 51 LintCode 33 | Java |
Medium | next-permutation | LeetCode 31 LintCode 52 | Java |
Easy | nth-to-last-node-in-list | LintCode 166 | Java |
Medium | number-of-airplanes-in-the-sky | LintCode 391 | Java Go |
Medium | number-of-islands | LeetCode 200 LintCode 433 | Java Go |
Medium | o1-check-power-of-2 | LintCode 142 | Java |
Easy | paint-fence | LintCode 514 | Java |
Medium | paint-house | LintCode 515 | Java |
Easy | palindrome-linked-list | LeetCode 234 LintCode 223 | Java |
Medium | palindrome-partitioning | LeetCode 131 LintCode 136 | Java |
Easy | partition-array-by-odd-and-even | LintCode 373 | Java |
Medium | partition-array | LintCode 31 | Java |
Medium | partition-list | LeetCode 86 LintCode 96 | Java |
Hard | patching-array | LeetCode 330 LintCode 1290 | C++ |
Medium | permutation-index | LintCode 197 | Java |
Hard | permutation-sequence | LeetCode 60 LintCode 388 | Java |
Medium | permutations-ii | LeetCode 47 LintCode 16 | Java |
Medium | permutations | LeetCode 46 LintCode 15 | Java |
Easy | plus-one | LeetCode 66 LintCode 407 | Java |
Medium | powx-n | LeetCode 50 LintCode 428 | Java |
Medium | previous-permutation | LintCode 51 | Java |
Medium | print-numbers-by-recursion | LintCode 371 | Java |
Easy | product-of-array-exclude-itself | LintCode 50 | Java |
Easy | recover-rotated-sorted-array | LintCode 39 | Java |
Medium | rehashing | LintCode 129 | Java |
Medium | remove-duplicates-from-sorted-array-ii | LeetCode 80 LintCode 101 | Java |
Easy | remove-duplicates-from-sorted-array | LeetCode 26 LintCode 100 | Java |
Medium | remove-duplicates-from-sorted-list-ii | LeetCode 82 LintCode 113 | Java Go |
Easy | remove-duplicates-from-sorted-list | LeetCode 83 LintCode 112 | Java Go |
Easy | remove-element | LeetCode 27 LintCode 172 | Java |
Easy | remove-linked-list-elements | LeetCode 203 LintCode 452 | Java |
Hard | remove-node-in-binary-search-tree | LintCode 87 | Java |
Medium | remove-nth-node-from-end-of-list | LeetCode 19 LintCode 174 | Java |
Medium | reorder-list | LeetCode 143 LintCode 99 | Java |
Medium | repeated-dna-sequences | LeetCode 187 LintCode 1335 | Java |
Medium | restore-ip-addresses | LeetCode 93 LintCode 426 | Java |
Medium | reverse-integer | LeetCode 7 LintCode 413 | Java |
Medium | reverse-linked-list-ii | LeetCode 92 LintCode 36 | Java Go |
Easy | reverse-linked-list | LeetCode 206 LintCode 35 | Java Go |
Hard | reverse-nodes-in-k-group | LeetCode 25 LintCode 450 | Java |
Hard | reverse-pairs | LeetCode 493 LintCode 532 | Java |
Medium | reverse-words-in-a-string | LeetCode 151 LintCode 53 | Java |
Easy | roman-to-integer | LeetCode 13 LintCode 419 | Java |
Medium | rotate-array | LeetCode 189 LintCode 1334 | C++ |
Medium | rotate-image | LeetCode 48 LintCode 161 | Java |
Medium | rotate-list | LeetCode 61 LintCode 170 | Java Go |
Easy | rotate-string | LeetCode 796 LintCode 8 | Java |
Medium | route-between-two-nodes-in-graph | LintCode 176 | Java |
Easy | same-tree | LeetCode 100 LintCode 469 | Java |
Medium | search-a-2d-matrix-ii | LeetCode 240 LintCode 38 | Java |
Medium | search-a-2d-matrix | LeetCode 74 LintCode 28 | Java |
Medium | search-for-a-range | LintCode 61 | Java |
Medium | search-in-rotated-sorted-array-ii | LeetCode 81 LintCode 63 | Java |
Medium | search-in-rotated-sorted-array | LeetCode 33 LintCode 62 | Java Python |
Easy | search-insert-position | LeetCode 35 LintCode 60 | Java |
Medium | search-range-in-binary-search-tree | LintCode 11 | Java |
Medium | segment-tree-build-ii | LintCode 439 | Java |
Medium | segment-tree-build | LintCode 201 | Java |
Medium | segment-tree-modify | LintCode 203 | Java |
Medium | segment-tree-query-ii | LintCode 247 | Java |
Medium | segment-tree-query | LintCode 202 | Java |
serialize-and-deserialize-binary-tree | LeetCode 297 LintCode 7 | Java | |
Medium | set-matrix-zeroes | LeetCode 73 LintCode 162 | Java |
Medium | shape-factory | LintCode 497 | Java |
Medium | shortest-unique-prefix | InterviewBit | C++ |
Medium | simplify-path | LeetCode 71 LintCode 421 | Java Go |
Medium | single-number-ii | LeetCode 137 LintCode 83 | Java |
Medium | single-number-iii | LeetCode 260 LintCode 84 | Java |
Easy | single-number | LeetCode 136 LintCode 82 | Java |
Easy | singleton | LintCode 204 | Java |
Medium | sort-colors-ii | LintCode 143 | Java |
Medium | sort-colors | LeetCode 75 LintCode 148 | Java |
Easy | sort-integers-ii | LintCode 464 | Java |
Easy | sort-integers | LintCode 463 | Java |
Medium | sort-letters-by-case | LintCode 49 | Java |
Medium | sort-list | LeetCode 148 LintCode 98 | Java Go |
Easy | space-replacement | LintCode 212 | Java |
Medium | spiral-matrix-ii | LeetCode 59 LintCode 381 | Java |
Medium | spiral-matrix | LeetCode 54 LintCode 374 | Java |
Easy | sqrtx | LeetCode 69 | Java |
Easy | string-permutation | LintCode 211 | Java |
Easy | subarray-sum | LintCode 138 | Java |
Medium | subsets-ii | LeetCode 90 LintCode 18 | Java |
Medium | subsets | LeetCode 78 LintCode 17 | Java |
Medium | subtree | LintCode 245 | Java |
Medium | sum-of-two-integers | LeetCode 371 | Java |
Medium | super-ugly-number | LeetCode 313 LintCode 518 | Java |
Medium | surrounded-regions | LeetCode 130 LintCode 477 | Java |
Medium | swap-nodes-in-pairs | LeetCode 24 LintCode 451 | Java |
Medium | swap-two-nodes-in-linked-list | LintCode 511 | Java |
Easy | symmetric-tree | LeetCode 101 LintCode 1360 | Java |
Hard | the-skyline-problem | LeetCode 218 LintCode 131 | Python |
Medium | the-smallest-difference | LintCode 387 | Java |
Medium | topological-sorting | LintCode 127 | Java |
Easy | toy-factory | LintCode 496 | Java |
Easy | trailing-zeros | LintCode 2 | Java |
Hard | trapping-rain-water | LeetCode 42 LintCode 363 | Java |
Medium | triangle | LeetCode 120 LintCode 109 | Java |
two-strings-are-anagrams | Java | ||
Easy | two-sum | LeetCode 1 LintCode 56 | Java |
Medium | ugly-number-ii | LeetCode 264 LintCode 4 | Java |
Easy | ugly-number | LeetCode 263 LintCode 517 | Java |
Medium | unique-binary-search-trees-ii | LeetCode 95 LintCode 164 | Java |
Medium | unique-binary-search-trees | LeetCode 96 LintCode 163 | Java |
Easy | unique-characters | LintCode 157 | Java |
Medium | unique-paths-ii | LeetCode 63 LintCode 115 | Java |
Medium | unique-paths | LeetCode 62 LintCode 114 | Java |
Medium | update-bits | LintCode 179 | Java |
Easy | valid-palindrome | LeetCode 125 LintCode 415 | Java |
Easy | valid-parentheses | LeetCode 20 LintCode 423 | Java |
Medium | valid-sudoku | LeetCode 36 LintCode 389 | Java |
Medium | validate-binary-search-tree | LeetCode 98 LintCode 95 | Java |
Medium | wiggle-sort | LintCode 508 | Java |
Hard | wood-cut | LintCode 183 | Java |
Hard | word-break-ii | LeetCode 140 LintCode 582 | Java |
Medium | word-break | LeetCode 139 LintCode 107 | Java |
Medium | word-count-map-reduce | LintCode 499 | Java |
Hard | word-ladder-ii | LeetCode 126 LintCode 121 | Java |
Hard | word-ladder | LeetCode 127 LintCode 120 | Java |
Medium | word-search | LeetCode 79 LintCode 123 | Java |