Master repo to hold all code challenge solutions by folder. Each challenge will include README with prompt, examples, explanations, and sources.
- https://leetcode.com/problems/maximum-subarray/
- https://www.hackerrank.com/challenges/jumping-on-the-clouds/problem
- https://www.hackerrank.com/challenges/ctci-array-left-rotation/problem
- https://leetcode.com/problems/product-of-array-except-self/
- https://leetcode.com/problems/subsets/ --> with Recursion
- https://leetcode.com/problems/3sum/
- https://www.hackerrank.com/challenges/2d-array/problem
- https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/
- https://www.codewars.com/kata/578aa45ee9fd15ff4600090d/train/python
- https://leetcode.com/problems/squares-of-a-sorted-array/
- Game Events found through Leetcode discussion
- https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix/
- https://www.hackerrank.com/challenges/minimum-swaps-2/problem
- https://www.hackerrank.com/challenges/new-year-chaos/problem
- https://leetcode.com/problems/subarray-sum-equals-k/ --> prefix sum
- https://leetcode.com/problems/minimum-absolute-difference/
- https://leetcode.com/problems/min-cost-climbing-stairs/
- https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/ --> binary search
- https://leetcode.com/problems/maximum-product-subarray/
- https://leetcode.com/problems/permutations/ --> with Recursion and Backtracking
- https://leetcode.com/problems/permutations-ii/ --> with Recursion and Backtracking
- https://leetcode.com/problems/pascals-triangle/ --> for-loop and recursion
- https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
- https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/
- https://leetcode.com/problems/degree-of-an-array/
- https://leetcode.com/problems/find-all-duplicates-in-an-array/
- https://leetcode.com/problems/two-sum/
- https://leetcode.com/problems/move-zeroes/
- https://www.hackerrank.com/challenges/repeated-string/problem
- https://www.hackerrank.com/challenges/ctci-ransom-note/problem
- https://www.hackerrank.com/challenges/two-strings/problem
- https://leetcode.com/problems/first-unique-character-in-a-string/
- https://leetcode.com/problems/valid-anagram/
- https://leetcode.com/problems/group-anagrams/
- https://leetcode.com/problems/how-many-numbers-are-smaller-than-the-current-number/
- https://leetcode.com/problems/find-common-characters/
- https://www.hackerrank.com/challenges/ctci-making-anagrams/problem
- https://www.hackerrank.com/challenges/alternating-characters/problem
- https://www.hackerrank.com/challenges/sherlock-and-valid-string/problem
- https://leetcode.com/problems/valid-palindrome-ii/
- https://leetcode.com/problems/reorganize-string/
- https://leetcode.com/problems/reformat-the-string/
- https://leetcode.com/problems/minimum-number-of-steps-to-make-two-strings-anagram/
- https://leetcode.com/problems/number-of-good-ways-to-split-a-string/
- https://leetcode.com/problems/valid-parentheses/
- https://www.hackerrank.com/challenges/sock-merchant/problem
- https://leetcode.com/problems/daily-temperatures/
- https://leetcode.com/problems/minimum-add-to-make-parentheses-valid/
- https://leetcode.com/problems/remove-duplicate-letters/
- https://leetcode.com/problems/minimum-remove-to-make-valid-parentheses/
- https://www.hackerrank.com/challenges/insert-a-node-into-a-sorted-doubly-linked-list/problem
- https://www.hackerrank.com/challenges/reverse-a-doubly-linked-list/problem
- https://leetcode.com/problems/merge-two-sorted-lists/
- https://leetcode.com/problems/flatten-a-multilevel-doubly-linked-list/
- https://leetcode.com/problems/middle-of-the-linked-list/
- https://leetcode.com/problems/palindrome-linked-list/
- https://leetcode.com/problems/reverse-linked-list/
- https://leetcode.com/problems/reverse-linked-list-ii/
- https://www.hackerrank.com/challenges/tree-height-of-a-binary-tree/problem
- https://www.hackerrank.com/challenges/binary-search-tree-lowest-common-ancestor/problem
- https://leetcode.com/problems/longest-univalue-path/
- https://leetcode.com/problems/minimum-depth-of-binary-tree/
- https://leetcode.com/problems/range-sum-of-bst/submissions/
- https://leetcode.com/problems/maximum-depth-of-binary-tree/
- https://leetcode.com/problems/average-of-levels-in-binary-tree/
- https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/
- https://leetcode.com/problems/cousins-in-binary-tree/
- https://leetcode.com/problems/search-in-a-binary-search-tree/
- https://leetcode.com/problems/n-ary-tree-postorder-traversal/
- https://leetcode.com/problems/n-ary-tree-preorder-traversal/
- https://leetcode.com/problems/maximum-depth-of-n-ary-tree/
- https://leetcode.com/problems/delete-nodes-and-return-forest/
- https://leetcode.com/problems/leaf-similar-trees/
- https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/
- https://leetcode.com/problems/deepest-leaves-sum/
- https://leetcode.com/problems/binary-tree-paths/
- https://leetcode.com/problems/path-sum/
- https://leetcode.com/problems/path-sum-ii/
- https://leetcode.com/problems/path-sum-iii/
- https://leetcode.com/problems/flatten-binary-tree-to-linked-list/
- https://leetcode.com/problems/binary-tree-level-order-traversal/
- https://leetcode.com/problems/all-possible-full-binary-trees/
- https://leetcode.com/problems/rotting-oranges/
- https://leetcode.com/problems/symmetric-tree/
- https://leetcode.com/problems/balanced-binary-tree/
- https://leetcode.com/problems/time-needed-to-inform-all-employees/
- https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/
- https://leetcode.com/problems/minimum-absolute-difference-in-bst/
- https://leetcode.com/problems/sum-root-to-leaf-numbers/
- https://leetcode.com/problems/binary-tree-maximum-path-sum/
- https://leetcode.com/problems/island-perimeter/
- https://leetcode.com/problems/flood-fill/
- https://leetcode.com/problems/max-area-of-island/
- https://leetcode.com/problems/number-of-islands/
- Longest Duplicate Path - similar to Max Area of Island
- https://leetcode.com/problems/find-the-town-judge/
- https://leetcode.com/problems/surrounded-regions/
- https://leetcode.com/problems/jump-game/
- https://leetcode.com/problems/jump-game-iii/
- https://leetcode.com/problems/maximal-square/ --> DP
- https://leetcode.com/problems/valid-palindrome/
- https://www.hackerrank.com/challenges/counting-valleys/
- https://leetcode.com/problems/longest-substring-without-repeating-characters/
- https://leetcode.com/problems/positions-of-large-groups/
- https://leetcode.com/problems/permutation-in-string/ (same/similar to https://leetcode.com/problems/find-all-anagrams-in-a-string/)
- https://leetcode.com/problems/assign-cookies/
- https://www.hackerrank.com/challenges/mark-and-toys/problem