LeetCode Total problems: 109, easy: 32, medium: 65, hard: 12 # Title Solution Difficulty 1 two-sum Kotlin Easy 2 add-two-numbers Kotlin Easy 3 longest-substring-without-repeating-characters Kotlin Medium 5 longest-palindromic-substring Kotlin Medium 6 zig-zag-conversion Kotlin Medium 7 reverse-integer Kotlin Easy 8 string-to-integer-atoi Kotlin Medium 9 palindrome-number Kotlin Easy 10 regular-expression-matching Kotlin Hard 11 container-with-most-water Kotlin Medium 12 integer-to-roman Kotlin Medium 13 roman-to-integer Kotlin Easy 14 longest-common-prefix Kotlin Easy 15 3-sum Kotlin Medium 16 3-sum-closest Kotlin Medium 17 letter-combinations-of-a-phone-number Kotlin Medium 18 4-sum Kotlin Medium 19 remove-nth-node-from-end-of-list Kotlin Medium 20 valid-parentheses Kotlin Easy 21 merge-two-sorted-lists Kotlin Easy 22 generate-parentheses Kotlin Medium 23 merge-k-sorted-lists Kotlin Hard 24 swap-nodes-in-pairs Kotlin Medium 25 reverse-nodes-in-k-group Kotlin Hard 26 remove-duplicates-from-sorted-array Kotlin Easy 27 remove-element Kotlin Easy 28 implement-str-str Kotlin Easy 29 divide-two-integers Kotlin Medium 31 next-permutation Kotlin Medium 32 longest-valid-parentheses Kotlin Hard 33 search-in-rotated-sorted-array. C++ Medium 34 find-first-and-last-position-of-element-in-sorted-array Kotlin Medium 38 count-and-say Kotlin Easy 44 wildcard-matching Kotlin Hard 50 pow-x-n Kotlin Medium 53 maximum-subarray Kotlin Easy 55 jump-game Kotlin Medium 60 permutation-sequence Kotlin Medium 62 unique-paths Kotlin Medium 63 unique-paths-ii Kotlin Medium 64 minimum-path-sum Kotlin Medium 67 add-binary Kotlin Easy 69 sqrt-x Kotlin Easy 70 climbing-stairs Kotlin Easy 72 edit-distance Kotlin Hard 85 maximal-rectangle Kotlin Hard 91 decode-ways Kotlin Medium 94 binary-tree-inorder-traversal Kotlin Medium 95 unique-binary-search-trees-ii Kotlin Medium 96 unique-binary-search-trees Kotlin Medium 98 validate-binary-search-tree Kotlin Medium 104 maximum-depth-of-binary-tree Kotlin Easy 112 path-sum Kotlin Easy 114 flatten-binary-tree-to-linked-list Kotlin Medium 120 triangle Kotlin Medium 127 word-ladder Kotlin Medium 134 gas-station Kotlin Medium 139 word-break Kotlin Medium 140 word-break-ii Kotlin Hard 162 find-peak-element Kotlin Medium 169 majority-element Kotlin Easy 198 house-robber Kotlin Easy 204 count-primes Kotlin Easy 207 course-schedule Kotlin Medium 210 course-schedule-ii Kotlin Medium 213 house-robber-ii Kotlin Medium 264 ugly-number-ii Kotlin Medium 268 missing-number Kotlin Easy 279 perfect-squares Kotlin Medium 300 longest-increasing-subsequence Kotlin Medium 303 range-sum-query-immutable Kotlin Easy 304 range-sum-query-2-d-immutable Kotlin Medium 310 minimum-height-trees Kotlin Medium 322 coin-change Kotlin Medium 329 longest-increasing-path-in-a-matrix Kotlin Hard 372 super-pow Kotlin Medium 402 remove-k-digits Kotlin Medium 515 find-largest-value-in-each-tree-row Kotlin Medium 621 task-scheduler Kotlin Medium 859 buddy-strings Kotlin Easy 869 reordered-power-of-2 Kotlin Medium 872 leaf-similar-trees Kotlin Easy 999 available-captures-for-rook Kotlin Easy 1038 binary-search-tree-to-greater-sum-tree Kotlin Medium 1305 all-elements-in-two-binary-search-trees Kotlin Medium 1306 jump-game-iii Kotlin Medium 1309 decrypt-string-from-alphabet-to-integer-mapping Kotlin Easy 1362 closest-divisors Kotlin Medium 1370 increasing-decreasing-string Kotlin Easy 1374 generate-a-string-with-characters-that-have-odd-counts Kotlin Easy 1375 bulb-switcher-iii Kotlin Medium 1376 time-needed-to-inform-all-employees Kotlin Medium 1377 frog-position-after-t-seconds Kotlin Hard 1380 lucky-numbers-in-a-matrix Kotlin Easy 1381 design-a-stack-with-increment-operation Kotlin Medium 1382 balance-a-binary-search-tree Kotlin Medium 1404 number-of-steps-to-reduce-a-number-in-binary-representation-to-one Kotlin Medium 1405 longest-happy-string Kotlin Medium 1472 design-browser-history Kotlin Medium 1473 paint-house-iii Kotlin Hard 1487 making-file-names-unique Kotlin Medium 1550 three-consecutive-odds Kotlin Easy 1551 minimum-operations-to-make-array-equal Kotlin Medium 1552 magnetic-force-between-two-balls Kotlin Medium 1582 special-positions-in-a-binary-matrix Kotlin Easy 1583 count-unhappy-friends Kotlin Medium 1584 min-cost-to-connect-all-points Kotlin Medium 1585 check-if-string-is-transformable-with-substring-sort-operations Kotlin Hard 1589 maximum-sum-obtained-of-any-permutation Kotlin Medium