String (1)
Title Difficulty Videos
Encode and Decode Strings Medium
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Hash table (4)
Title Difficulty Videos
Two Sum Easy
Contains Duplicate 1 - Check if array has duplicates Easy
Valid Anagram Easy
Group Anagrams Medium
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Two pointers (6)
Title Difficulty Videos
Valid Palindrome Easy
Backspace String Compare Easy
Container With Most Water Medium
3Sum0 - Find three elements in an array that sum to a zero Medium
Dutch National Flag DNF Medium
Trapping Rain Water Hard
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Sliding window (6)
Title Difficulty Videos
Longest Substring Without Repeating Characters Medium
Longest Substring with Same Letters after Replacement Medium
Find anagrams of a string in another string Medium
Count Number of Nice Subarrays Medium
Minimum Window Substring Hard
Sliding Window Maximum Hard
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Binary search (4)
Title Difficulty Videos
Binary Search on Sorted Array Easy
Search in Rotated Sorted Array Medium
Find Minimum in Rotated Sorted Array Medium
Median of Two Sorted Arrays Hard
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Sorting (3)
Title Difficulty Videos
Largest Number From Given Numbers Medium
Kth Largest Element in an Array Medium
Sort Characters By Frequency Medium
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Bit manipulation (6)
Title Difficulty Videos
Single Number 1 - All elements except one occur twice Easy
Reverse Bits Easy
Number of 1 Bits Easy
Missing Number Easy
Counting Bits Easy
Sum of Two Integers Medium
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Math (2)
Title Difficulty Videos
Happy Number Easy
Maximum Points on a Line Hard
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Linked list (6)
Title Difficulty Videos
Merge Two Sorted Linked Lists Easy
Linked List Cycle 1 - Detect Cycle Easy
Intersection of Two Linked Lists Easy
Reverse Linked List Easy
Remove Nth Node From End of List Medium
Reorder List such that i-th element points to n-i th element Medium
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Stack (5)
Title Difficulty Videos
Valid Parentheses Easy
Implement Queue using Stacks Easy
Min Stack Medium
Daily Temperatures Medium
Largest Rectangle in Histogram Hard
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Tree (13)
Title Difficulty Videos
Same Tree Easy
Symmetric Binary Tree Easy
Maximum Depth of Binary Tree Easy
Invert Binary Tree Easy
Subtree of Another Tree Easy
Validate Binary Search Tree Medium
Binary Tree Level Order Traversal - Level by Level Medium
Construct Binary Tree from Inorder and Preorder Traversal Medium
Kth Smallest Element in a BST Medium
Lowest Common Ancestor of a Binary Search Tree Medium
Replace Words Medium
Binary Tree Path Sum - Maximum between any two nodes Hard
Serialize and Deserialize Binary Tree Hard
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Trie (3)
Title Difficulty Videos
Implement Trie Medium
Design Add and Search Words Data Structure Medium
Word Search 2 - Return All Words Hard
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Graph (8)
Title Difficulty Videos
Longest Consecutive Sequence Medium
Clone Undirected Graph Medium
Number of Islands Medium
Course Schedule 1 - Is it Possible Medium
Graph Valid Tree Medium
Pacific Atlantic Water Flow Medium
Word Ladder 1 - Get Ladder Length Hard
Alien Dictionary Hard
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Backtracking (5)
Title Difficulty Videos
Combination Sum 1 Medium
Permutations of Array 1 Medium
Subsets 1 Medium
Word Search 1 - Find if word exists Medium
N-Queens Hard
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Greedy (2)
Title Difficulty Videos
Jump Game 1 - Check if it reaches last index Medium
Gas Station Medium
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Interval (6)
Title Difficulty Videos
Meeting Rooms 1 - Can person attend all meetings Easy
Maximum Intervals Overlap Count Medium
Merge Overlapping Intervals Medium
Insert Interval Medium
Meeting Rooms 2 - Minimum Meeting Rooms Required Medium
Non-overlapping Intervals Medium
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Dynamic programming (15)
Title Difficulty Videos
Climbing Stairs - Take atmost 2 Steps Easy
Best Time To Buy And Sell Stock 1 - only one transaction Easy
Longest Palindromic Substring Medium
Maximum Subarray Sum Medium
Unique Paths in Grid 1 - Count all paths moving right or down Medium
Decode Ways Medium
Word Break 1 - Check if word is breakable Medium
Maximum Product Subarray Medium
House Robber Medium
House Robber 2 - Houses in circle Medium
Longest Increasing Subsequence LIS Medium
Coin Change with Fewest Number of Coins Given Infinite Supply Medium
Partition Equal Subset Sum Medium
Palindromic Substrings Medium
Longest Common Subsequence LCS 1 - Get Length Medium
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Union find (4)
Title Difficulty Videos
Number of Connected Components in an Undirected Graph Medium
Evaluate Division Medium
Redundant Connection Medium
Accounts Merge Medium
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Heap priority queue (4)
Title Difficulty Videos
Top K Frequent Elements Medium
Task Scheduler Medium
Merge K Sorted Lists Hard
Find Median from Data Stream Hard
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Matrix (4)
Title Difficulty Videos
Matrix Diagonal Sum Easy
Rotate n x n matrix by 90 degrees Medium
Spiral Matrix 1 - Return Medium
Set Matrix Zeros Medium
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Prefix sum (1)
Title Difficulty Videos
Product of Array Except Self Medium