DSA Interview 150

1 Longest Consecutive Sequence Medium Arrays & Hashing 2 Encode and Decode Strings Medium Arrays & Hashing 3 Valid Sudoku Medium Arrays & Hashing 4 Product of Array Except Self Medium Arrays & Hashing 5 Top K Frequent Elements Medium Arrays & Hashing 6 Group Anagrams Medium Arrays & Hashing 7 Two Sum Easy Arrays & Hashing 8 Valid Anagram Easy Arrays & Hashing 9 Contains Duplicate Easy Arrays & Hashing

1 Trapping Rain Water Hard Two Pointers 2 Container With Most Water Medium Two Pointers 3 3Sum Medium Two Pointers 4 Two Sum II - Input Array Is Sorted Medium Two Pointers 5 Valid Palindrome Easy Two Pointers

1 Sliding Window Maximum Hard Sliding Window 2 Minimum Window Substring Hard Sliding Window 3 Permutation in String Medium Sliding Window 4 Longest Repeating Character Replacement Medium Sliding Window 5 Longest Substring Without Repeating Characters Medium Sliding Window 6 Best Time to Buy and Sell Stock Easy Sliding Window

1 Largest Rectangle in Histogram Hard Stack 2 Car Fleet Medium Stack 3 Daily Temperatures Medium Stack 4 Generate Parentheses Medium Stack 5 Evaluate Reverse Polish Notation Medium Stack 6 Min Stack Medium Stack 7 Valid Parentheses Easy Stack

1 Median of Two Sorted Arrays Hard Binary Search 2 Time Based Key-Value Store Medium Binary Search 3 Search in Rotated Sorted Array Medium Binary Search 4 Find Minimum in Rotated Sorted Array Medium Binary Search 5 Koko Eating Bananas Medium Binary Search 6 Search a 2D Matrix Medium Binary Search 7 Binary Search Easy Binary Search

1 Reverse Nodes in k-Group Hard Linked List 2 Merge k Sorted Lists Hard Linked List 3 LRU Cache Medium Linked List 4 Find the Duplicate Number Medium Linked List 5 Linked List Cycle Easy Linked List 6 Add Two Numbers Medium Linked List 7 Copy List with Random Pointer Medium Linked List 8 Remove Nth Node From End of List Medium Linked List 9 Reorder List Medium Linked List 10 Merge Two Sorted Lists Easy Linked List 11 Reverse Linked List Easy Linked List

1 Serialize and Deserialize Binary Tree Hard Trees 2 Binary Tree Maximum Path Sum Hard Trees 3 Construct Binary Tree from Preorder and Inorder Traversal Medium Trees 4 Kth Smallest Element in a BST Medium Trees 5 Validate Binary Search Tree Medium Trees 6 Count Good Nodes in Binary Tree Medium Trees 7 Binary Tree Right Side View Medium Trees 8 Binary Tree Level Order Traversal Medium Trees 9 Lowest Common Ancestor of a Binary Search Tree Medium Trees 10 Subtree of Another Tree Easy Trees 11 Same Tree Easy Trees 12 Balanced Binary Tree Easy Trees 13 Diameter of Binary Tree Easy Trees 14 Maximum Depth of Binary Tree Easy Trees 15 Invert Binary Tree Easy Trees

1 Word Search II Hard Tries 2 Design Add and Search Words Data Structure Medium Tries 3 Implement Trie (Prefix Tree) Medium Tries

1 Find Median from Data Stream Hard Heap / Priority Queue 2 Design Twitter Medium Heap / Priority Queue 3 Task Scheduler Medium Heap / Priority Queue 4 Kth Largest Element in an Array Medium Heap / Priority Queue 5 K Closest Points to Origin Medium Heap / Priority Queue 6 Last Stone Weight Easy Heap / Priority Queue 7 Kth Largest Element in a Stream Easy Heap / Priority Queue

1 N-Queens Hard Backtracking 2 Letter Combinations of a Phone Number Medium Backtracking 3 Palindrome Partitioning Medium Backtracking 4 Word Search Medium Backtracking 5 Combination Sum II Medium Backtracking 6 Subsets II Medium Backtracking 7 Permutations Medium Backtracking 8 Combination Sum Medium Backtracking 9 Subsets Medium Backtracking

1 Word Ladder Hard Graphs 2 Graph Valid Tree Medium Graphs 3 Number of Connected Components in an Undirected Graph Medium Graphs 4 Redundant Connection Medium Graphs 5 Course Schedule II Medium Graphs 6 Course Schedule Medium Graphs 7 Walls and Gates Medium Graphs 8 Rotting Oranges Medium Graphs 9 Surrounded Regions Medium Graphs 10 Pacific Atlantic Water Flow Medium Graphs 11 Max Area of Island Medium Graphs 12 Clone Graph Medium Graphs 13 Number of Islands Medium Graphs

1 Cheapest Flights Within K Stops Medium Advanced Graphs 2 Alien Dictionary Hard Advanced Graphs 3 Swim in Rising Water Hard Advanced Graphs 4 Network Delay Time Medium Advanced Graphs 5 Min Cost to Connect All Points Medium Advanced Graphs 6 Reconstruct Itinerary Hard Advanced Graphs

1 Partition Equal Subset Sum Medium 1-D Dynamic Programming 2 Longest Increasing Subsequence Medium 1-D Dynamic Programming 3 Word Break Medium 1-D Dynamic Programming 4 Maximum Product Subarray Medium 1-D Dynamic Programming 5 Coin Change Medium 1-D Dynamic Programming 6 Decode Ways Medium 1-D Dynamic Programming 7 Palindromic Substrings Medium 1-D Dynamic Programming 8 Longest Palindromic Substring Medium 1-D Dynamic Programming 9 House Robber II Medium 1-D Dynamic Programming 10 House Robber Medium 1-D Dynamic Programming 11 Min Cost Climbing Stairs Easy 1-D Dynamic Programming 12 Climbing Stairs Easy 1-D Dynamic Programming

1 Regular Expression Matching Hard 2-D Dynamic Programming 2 Burst Balloons Hard 2-D Dynamic Programming 3 Edit Distance Hard 2-D Dynamic Programming 4 Distinct Subsequences Hard 2-D Dynamic Programming 5 Longest Increasing Path in a Matrix Hard 2-D Dynamic Programming 6 Interleaving String Medium 2-D Dynamic Programming 7 Target Sum Medium 2-D Dynamic Programming 8 Coin Change 2 Medium 2-D Dynamic Programming 9 Best Time to Buy and Sell Stock with Cooldown Medium 2-D Dynamic Programming 10 Longest Common Subsequence Medium 2-D Dynamic Programming 11 Unique Paths Medium 2-D Dynamic Programming

1 Valid Parenthesis String Medium Greedy 2 Partition Labels Medium Greedy 3 Merge Triplets to Form Target Triplet Medium Greedy 4 Hand of Straights Medium Greedy 5 Gas Station Medium Greedy 6 Jump Game II Medium Greedy 7 Jump Game Medium Greedy 8 Maximum Subarray Medium Greedy

1 Minimum Interval to Include Each Query Hard Intervals 2 Meeting Rooms II Medium Intervals 3 Meeting Rooms Easy Intervals 4 Non-overlapping Intervals Medium Intervals 5 Merge Intervals Medium Intervals 6 Insert Interval Medium Intervals

1 Detect Squares Medium Math & Geometry 2 Multiply Strings Medium Math & Geometry 3 Pow(x, n) Medium Math & Geometry 4 Plus One Easy Math & Geometry 5 Happy Number Easy Math & Geometry 6 Set Matrix Zeroes Medium Math & Geometry 7 Spiral Matrix Medium Math & Geometry 8 Rotate Image Medium Math & Geometry

1 Reverse Integer Medium Bit Manipulation 2 Sum of Two Integers Medium Bit Manipulation 3 Missing Number Easy Bit Manipulation 4 Reverse Bits Easy Bit Manipulation 5 Counting Bits Easy Bit Manipulation 6 Number of 1 Bits Easy Bit Manipulation 7 Single Number Easy Bit Manipulation