Ratta 67

67 essential easy and medium problems. Covers every core pattern — arrays, trees, graphs, DP, and more — without the hard-mode spikes.

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01.Two Sumeasy 02.Contains Duplicateeasy 03.Valid Anagrameasy 04.Group Anagramsmedium 05.Top K Frequent Elementsmedium 06.Product of Array Except Selfmedium 07.Encode and Decode Stringsmedium 08.Longest Consecutive Sequencemedium 09.Valid Palindromeeasy 10.3Summedium 11.Container With Most Watermedium 12.Best Time to Buy and Sell Stockeasy 13.Longest Substring Without Repeating Charactersmedium 14.Longest Repeating Character Replacementmedium 15.Valid Parentheseseasy 16.Find Minimum in Rotated Sorted Arraymedium 17.Search in Rotated Sorted Arraymedium 18.Reverse Linked Listeasy 19.Merge Two Sorted Listseasy 20.Linked List Cycleeasy 21.Reorder Listmedium 22.Remove Nth Node From End of Listmedium 23.Invert Binary Treeeasy 24.Maximum Depth of Binary Treeeasy 25.Same Treeeasy 26.Subtree of Another Treeeasy 27.Lowest Common Ancestor of a Binary Search Treemedium 28.Binary Tree Level Order Traversalmedium 29.Validate Binary Search Treemedium 30.Kth Smallest Element in a BSTmedium 31.Construct Binary Tree from Preorder and Inorder Traversalmedium 32.Implement Trie (Prefix Tree)medium 33.Design Add and Search Words Data Structuremedium 34.Word Searchmedium 35.Number of Islandsmedium 36.Clone Graphmedium 37.Pacific Atlantic Water Flowmedium 38.Course Schedulemedium 39.Graph Valid Treemedium 40.Number of Connected Components in an Undirected Graphmedium 41.Climbing Stairseasy 42.House Robbermedium 43.House Robber IImedium 44.Longest Palindromic Substringmedium 45.Decode Waysmedium 46.Coin Changemedium 47.Maximum Product Subarraymedium 48.Word Breakmedium 49.Longest Increasing Subsequencemedium 50.Longest Common Subsequencemedium 51.Unique Pathsmedium 52.Combination Sum IVmedium 53.Jump Gamemedium 54.Maximum Subarraymedium 55.Insert Intervalmedium 56.Merge Intervalsmedium 57.Non-overlapping Intervalsmedium 58.Meeting Roomseasy 59.Meeting Rooms IImedium 60.Set Matrix Zeroesmedium 61.Spiral Matrixmedium 62.Rotate Imagemedium 63.Number of 1 Bitseasy 64.Counting Bitseasy 65.Reverse Bitseasy 66.Missing Numbereasy 67.Sum of Two Integersmedium