Leetcode - Quick 75 problems refresher
75 problems refresher⌗
Array⌗
- Two Sum - https://leetcode.com/problems/two-sum/
- Best Time to Buy and Sell Stock - https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
- Contains Duplicate - https://leetcode.com/problems/contains-duplicate/
- Product of Array Except Self - https://leetcode.com/problems/product-of-array-except-self/
- Maximum Subarray - https://leetcode.com/problems/maximum-subarray/
- Maximum Product Subarray - https://leetcode.com/problems/maximum-product-subarray/
- Find Minimum in Rotated Sorted Array - https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/
- Search in Rotated Sorted Array - https://leetcode.com/problems/search-in-rotated-sorted-array/
- 3Sum - https://leetcode.com/problems/3sum/
- Container With Most Water - https://leetcode.com/problems/container-with-most-water/
Binary⌗
- Sum of Two Integers - https://leetcode.com/problems/sum-of-two-integers/
- Number of 1 Bits - https://leetcode.com/problems/number-of-1-bits/
- Counting Bits - https://leetcode.com/problems/counting-bits/
- Missing Number - https://leetcode.com/problems/missing-number/
- Reverse Bits - https://leetcode.com/problems/reverse-bits/
Dynamic Programming⌗
- Climbing Stairs - https://leetcode.com/problems/climbing-stairs/
- Coin Change - https://leetcode.com/problems/coin-change/
- Longest Increasing Subsequence - https://leetcode.com/problems/longest-increasing-subsequence/
- Longest Common Subsequence -
- Word Break Problem - https://leetcode.com/problems/word-break/
- Combination Sum - https://leetcode.com/problems/combination-sum-iv/
- House Robber - https://leetcode.com/problems/house-robber/
- House Robber II - https://leetcode.com/problems/house-robber-ii/
- Decode Ways - https://leetcode.com/problems/decode-ways/
- Unique Paths - https://leetcode.com/problems/unique-paths/
- Jump Game - https://leetcode.com/problems/jump-game/
Graph⌗
- Clone Graph - https://leetcode.com/problems/clone-graph/
- Course Schedule - https://leetcode.com/problems/course-schedule/
- Pacific Atlantic Water Flow - https://leetcode.com/problems/pacific-atlantic-water-flow/
- Number of Islands - https://leetcode.com/problems/number-of-islands/
- Longest Consecutive Sequence - https://leetcode.com/problems/longest-consecutive-sequence/
- Alien Dictionary (Leetcode Premium) - https://leetcode.com/problems/alien-dictionary/
- Graph Valid Tree (Leetcode Premium) - https://leetcode.com/problems/graph-valid-tree/
- Number of Connected Components in an Undirected Graph (Leetcode Premium) -https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/
Interval⌗
- Insert Interval - https://leetcode.com/problems/insert-interval/
- Merge Intervals - https://leetcode.com/problems/merge-intervals/
- Non-overlapping Intervals - https://leetcode.com/problems/non-overlapping-intervals/
- Meeting Rooms (Leetcode Premium) - https://leetcode.com/problems/meeting-rooms/
- Meeting Rooms II (Leetcode Premium) - https://leetcode.com/problems/meeting-rooms-ii/
Linked List⌗
- Reverse a Linked List - https://leetcode.com/problems/reverse-linked-list/
- Detect Cycle in a Linked List - https://leetcode.com/problems/linked-list-cycle/
- Merge Two Sorted Lists - https://leetcode.com/problems/merge-two-sorted-lists/
- Merge K Sorted Lists - https://leetcode.com/problems/merge-k-sorted-lists/
- Remove Nth Node From End Of List - https://leetcode.com/problems/remove-nth-node-from-end-of-list/
- Reorder List - https://leetcode.com/problems/reorder-list/
Matrix⌗
- Set Matrix Zeroes - https://leetcode.com/problems/set-matrix-zeroes/
- Spiral Matrix - https://leetcode.com/problems/spiral-matrix/
- Rotate Image - https://leetcode.com/problems/rotate-image/
- Word Search - https://leetcode.com/problems/word-search/
String⌗
Longest Substring Without Repeating Characters - https://leetcode.com/problems/longest-substring-without-repeating-characters/
Longest Repeating Character Replacement -
https://leetcode.com/problems/longest-repeating-character-replacement/
Minimum Window Substring - https://leetcode.com/problems/minimum-window-substring/
Valid Anagram - https://leetcode.com/problems/valid-anagram/
Group Anagrams - https://leetcode.com/problems/group-anagrams/
Valid Parentheses - https://leetcode.com/problems/valid-parentheses/
Valid Palindrome - https://leetcode.com/problems/valid-palindrome/
Longest Palindromic Substring - https://leetcode.com/problems/longest-palindromic-substring/
Palindromic Substrings - https://leetcode.com/problems/palindromic-substrings/
Encode and Decode Strings (Leetcode Premium) -https://leetcode.com/problems/encode-and-decode-strings/
Tree⌗
- Maximum Depth of Binary Tree - https://leetcode.com/problems/maximum-depth-of-binary-tree/
- Same Tree - https://leetcode.com/problems/same-tree/
- Invert/Flip Binary Tree - https://leetcode.com/problems/invert-binary-tree/
- Binary Tree Maximum Path Sum - https://leetcode.com/problems/binary-tree-maximum-path-sum/
- Binary Tree Level Order Traversal - https://leetcode.com/problems/binary-tree-level-order-traversal/
- Serialize and Deserialize Binary Tree - https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
- Subtree of Another Tree - https://leetcode.com/problems/subtree-of-another-tree/
- Construct Binary Tree from Preorder and Inorder Traversal -https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/
- Validate Binary Search Tree - https://leetcode.com/problems/validate-binary-search-tree/
- Kth Smallest Element in a BST - https://leetcode.com/problems/kth-smallest-element-in-a-bst/
- Lowest Common Ancestor of BST - https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/
- Implement Trie (Prefix Tree) - https://leetcode.com/problems/implement-trie-prefix-tree/
- Add and Search Word - https://leetcode.com/problems/add-and-search-word-data-structure-design/
- Word Search II - https://leetcode.com/problems/word-search-ii/
Heap⌗
- Merge K Sorted Lists - https://leetcode.com/problems/merge-k-sorted-lists/
- Top K Frequent Elements - https://leetcode.com/problems/top-k-frequent-elements/
- Find Median from Data Stream - https://leetcode.com/problems/find-median-from-data-stream/
Difficulty wise :
| ID | Problem Name | Problem Link | Difficulty | Status |
|---|---|---|---|---|
| 295 | Find Median from Data Stream | https://leetcode.com/problems/find-median-from-data-stream | Difficult | |
| 269 | Alien Dictionary | https://leetcode.com/problems/alien-dictionary | Difficult | |
| 212 | Word Search II | https://leetcode.com/problems/word-search-ii | Difficult | |
| 124 | Binary Tree Maximum Path Sum | https://leetcode.com/problems/binary-tree-maximum-path-sum | Difficult | Solved |
| 76 | Minimum Window Substring | https://leetcode.com/problems/minimum-window-substring | Difficult | Solved |
| 23 | Merge k Sorted Lists | https://leetcode.com/problems/merge-k-sorted-list | Difficult | |
| 572 | Subtree of Another Tree | https://leetcode.com/problems/subtree-of-another-tree | Easy | |
| 338 | Counting Bits | https://leetcode.com/problems/counting-bits | Easy | |
| 268 | Missing Number | https://leetcode.com/problems/missing-number | Easy | Solved |
| 252 | Meeting Rooms | https://leetcode.com/problems/meeting-rooms | Easy | |
| 242 | Valid Anagram | https://leetcode.com/problems/valid-anagram | Easy | Solved |
| 235 | Lowest Common Ancestor of a Binary Search Tree | https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree | Easy | Solved |
| 226 | Invert Binary Tree | https://leetcode.com/problems/invert-binary-tree | Easy | Solved |
| 217 | Contains Duplicate | https://leetcode.com/problems/contains-duplicate | Easy | Solved |
| 206 | Reverse Linked List | https://leetcode.com/problems/reverse-linked-list | Easy | Solved |
| 191 | Number of 1 Bits | https://leetcode.com/problems/number-of-1-bits | Easy | Solved |
| 190 | Reverse Bits | https://leetcode.com/problems/reverse-bits | Easy | Solved |
| 141 | Linked List Cycle | https://leetcode.com/problems/linked-list-cycle | Easy | Solved |
| 125 | Valid Palindrome | https://leetcode.com/problems/valid-palindrome | Easy | Solved |
| 121 | Best Time to Buy and Sell Stock | https://leetcode.com/problems/best-time-to-buy-and-sell-stock | Easy | Solved |
| 104 | Maximum Depth of Binary Tree | https://leetcode.com/problems/maximum-depth-of-binary-tree | Easy | Solved |
| 100 | Same Tree | https://leetcode.com/problems/same-tree | Easy | Solved |
| 70 | Climbing Stairs | https://leetcode.com/problems/climbing-stairs | Easy | Solved |
| 53 | Maximum Subarray | https://leetcode.com/problems/maximum-subarray | Easy | Solved |
| 21 | Merge Two Sorted Lists | https://leetcode.com/problems/merge-two-sorted-lists | Easy | Solved |
| 20 | Valid Parentheses | https://leetcode.com/problems/valid-parentheses | Easy | Solved |
| 1 | Two Sum | https://leetcode.com/problems/two-sum | Easy | Solved |
| 1250 | Longest Common Subsequence | https://leetcode.com/problems/longest-common-subsequence | Medium | Solved |
| 647 | Palindromic Substrings | https://leetcode.com/problems/palindromic-substrings | Medium | |
| 449 | Serialize and Deserialize BST | https://leetcode.com/problems/serialize-and-deserialize-bst | Medium | |
| 435 | Non-overlapping Intervals | https://leetcode.com/problems/non-overlapping-intervals | Medium | |
| 424 | Longest Repeating Character Replacement | https://leetcode.com/problems/null | Medium | |
| 417 | Pacific Atlantic Water Flow | https://leetcode.com/problems/pacific-atlantic-water-flow | Medium | |
| 371 | Sum of Two Integers | https://leetcode.com/problems/sum-of-two-integers | Medium | Solved |
| 347 | Top K Frequent Elements | https://leetcode.com/problems/top-k-frequent-elements | Medium | |
| 323 | Number of Connected Components in an Undirected Graph | https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph | Medium | |
| 322 | Coin Change | https://leetcode.com/problems/coin-change | Medium | Solved |
| 300 | Longest Increasing Subsequence | https://leetcode.com/problems/longest-increasing-subsequence | Medium | Solved |
| 271 | Encode and Decode Strings | https://leetcode.com/problems/encode-and-decode-strings | Medium | |
| 261 | Graph Valid Tree | https://leetcode.com/problems/graph-valid-tree | Medium | |
| 253 | Meeting Rooms II | https://leetcode.com/problems/meeting-rooms-ii | Medium | |
| 238 | Product of Array Except Self | https://leetcode.com/problems/product-of-array-except-self | Medium | |
| 236 | Lowest Common Ancestor of a Binary Tree | https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree | Medium | Solved |
| 230 | Kth Smallest Element in a BST | https://leetcode.com/problems/kth-smallest-element-in-a-bst | Medium | Solved |
| 213 | House Robber II | https://leetcode.com/problems/house-robber-ii | Medium | |
| 211 | Design Add and Search Words Data Structure | https://leetcode.com/problems/add-and-search-word | Medium | |
| 208 | Implement Trie (Prefix Tree) | https://leetcode.com/problems/implement-trie-prefix-tree | Medium | |
| 207 | Course Schedule | https://leetcode.com/problems/course-schedule | Medium | Solved |
| 200 | Number of Islands | https://leetcode.com/problems/number-of-islands | Medium | Solved |
| 198 | House Robber | https://leetcode.com/problems/house-robber | Medium | Solved |
| 153 | Find Minimum in Rotated Sorted Array | https://leetcode.com/problems/find-minimum-in-rotated-sorted-array | Medium | Solved |
| 152 | Maximum Product Subarray | https://leetcode.com/problems/maximum-product-subarray | Medium | Solved |
| 143 | Reorder List | https://leetcode.com/problems/reorder-list | Medium | Solved |
| 139 | Word Break | https://leetcode.com/problems/word-break | Medium | Solved |
| 133 | Clone Graph | https://leetcode.com/problems/clone-graph | Medium | Solved |
| 128 | Longest Consecutive Sequence | https://leetcode.com/problems/longest-consecutive-sequence | Medium | Solved |
| 105 | Construct Binary Tree from Preorder and Inorder Traversal | https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal | Medium | |
| 102 | Binary Tree Level Order Traversal | https://leetcode.com/problems/binary-tree-level-order-traversal | Medium | Solved |
| 98 | Validate Binary Search Tree | https://leetcode.com/problems/validate-binary-search-tree | Medium | Solved |
| 91 | Decode Ways | https://leetcode.com/problems/decode-ways | Medium | Solved |
| 79 | Word Search | https://leetcode.com/problems/word-search | Medium | Solved |
| 73 | Set Matrix Zeroes | https://leetcode.com/problems/set-matrix-zeroes | Medium | Solved |
| 62 | Unique Paths | https://leetcode.com/problems/unique-paths | Medium | Solved |
| 57 | Insert Interval | https://leetcode.com/problems/insert-interval | Medium | |
| 56 | Merge Intervals | https://leetcode.com/problems/merge-intervals | Medium | Solved |
| 55 | Jump Game | https://leetcode.com/problems/jump-game | Medium | Solved |
| 54 | Spiral Matrix | https://leetcode.com/problems/spiral-matrix | Medium | Solved |
| 49 | Group Anagrams | https://leetcode.com/problems/group-anagrams | Medium | Solved |
| 48 | Rotate Image | https://leetcode.com/problems/rotate-image | Medium | |
| 39 | Combination Sum | https://leetcode.com/problems/combination-sum | Medium | Solved |
| 33 | Search in Rotated Sorted Array | https://leetcode.com/problems/search-in-rotated-sorted-array | Medium | Solved |
| 19 | Remove Nth Node From End of List | https://leetcode.com/problems/remove-nth-node-from-end-of-list | Medium | Solved |
| 15 | 3Sum | https://leetcode.com/problems/3sum | Medium | Solved |
| 11 | Container With Most Water | https://leetcode.com/problems/container-with-most-water | Medium | Solved |
| 5 | Longest Palindromic Substring | https://leetcode.com/problems/longest-palindromic-substring | Medium | Solved |
| 3 | Longest Substring Without Repeating Characters | https://leetcode.com/problems/longest-substring-without-repeating-characters | Medium | Solved |