Difficulty

Medium DSA Problems with Solutions

Where most interview questions live. Patterns get combined, edge cases multiply, and the right data structure matters.

Medium problems are the bulk of the FAANG interview pool. They test whether you can combine two patterns (sliding window + hash map, BFS + state encoding, DP + bitmask), reason about edge cases under time pressure, and pick the right data structure on the first try. If you can solve mediums fluently, you're ready for most onsite rounds. Every medium problem on Ratta includes multiple approaches — typically a brute-force first, then the optimized solution — so you can see the progression rather than memorizing a single template.

Arrays & Hashing · 8

Product of Array Except Selfmedium Maximum Subarraymedium Longest Consecutive Sequencemedium Group Anagramsmedium Set Matrix Zeroesmedium Spiral Matrixmedium Rotate Imagemedium Encode and Decode Stringsmedium

Two Pointers · 2

3Summedium Container With Most Watermedium

Sliding Window · 2

Longest Substring Without Repeating Charactersmedium Longest Repeating Character Replacementmedium

Binary Search · 2

Find Minimum in Rotated Sorted Arraymedium Search in Rotated Sorted Arraymedium

Linked List · 2

Remove Nth Node From End of Listmedium Reorder Listmedium

Trees · 5

Binary Tree Level Order Traversalmedium Construct Binary Tree from Preorder and Inorder Traversalmedium Validate Binary Search Treemedium Kth Smallest Element in a BSTmedium Lowest Common Ancestor of a Binary Search Treemedium

Tries · 2

Implement Trie (Prefix Tree)medium Design Add and Search Words Data Structuremedium

Heap / Priority Queue · 1

Top K Frequent Elementsmedium

Backtracking · 1

Word Searchmedium

Graphs · 6

Clone Graphmedium Course Schedulemedium Pacific Atlantic Water Flowmedium Number of Islandsmedium Graph Valid Treemedium Number of Connected Components in an Undirected Graphmedium

Dynamic Programming · 12

Maximum Product Subarraymedium Coin Changemedium Longest Increasing Subsequencemedium Longest Common Subsequencemedium Word Breakmedium Combination Sum IVmedium House Robbermedium House Robber IImedium Decode Waysmedium Unique Pathsmedium Longest Palindromic Substringmedium Palindromic Substringsmedium

Greedy · 1

Jump Gamemedium

Intervals · 4

Insert Intervalmedium Merge Intervalsmedium Non-overlapping Intervalsmedium Meeting Rooms IImedium

Bit Manipulation · 1

Sum of Two Integersmedium