StatusProblemTopicsDifficultyAcceptance
Remove Duplicates from Sorted Array
ArraysTwo Pointers
easy58%
Best Time to Buy and Sell Stock
ArraysSliding Window
easy61%
Two Sum
Arrays
easy57%
Valid Palindrome
StringsTwo Pointers
easy56%
Merge Sorted Array
ArraysTwo Pointers
easy55%
Move Zeroes
ArraysTwo Pointers
easy67%
Product of Array Except Self
Arrays
medium55%
Container With Most Water
ArraysTwo Pointers
medium47%
3Sum
ArraysTwo Pointers
medium43%
Longest Substring Without Repeating Characters
StringsSliding Window
medium42%
Group Anagrams
StringsArrays
medium55%
Longest Palindromic Substring
StringsTwo Pointers
medium42%
Minimum Size Subarray Sum
ArraysSliding Window
medium48%
String to Integer (atoi)
Strings
medium41%
Zigzag Conversion
Strings
medium50%
Find All Anagrams in a String
StringsSliding Window
medium52%
Rotate Array
Arrays
medium43%
Longest Repeating Character Replacement
StringsSliding Window
medium44%
Permutation in String
StringsSliding Window
medium50%
Next Permutation
ArraysTwo Pointers
medium44%
Maximum Subarray
Arrays
medium52%
Minimum Window Substring
StringsSliding Window
hard40%
Substring with Concatenation of All Words
StringsSliding Window
hard36%
First Missing Positive
Arrays
hard38%
Sliding Window Maximum
ArraysSliding Window
hard42%
Median of Two Sorted Arrays
ArraysTwo Pointers
hard37%
Longest Valid Parentheses
StringsTwo Pointers
hard36%
Smallest Window Containing All Characters
StringsSliding Window
hard38%
Reverse Linked List
Linked List
easy69%
Linked List Cycle
Linked List
easy59%
Maximum Depth of Binary Tree
Binary Tree
easy70%
Invert Binary Tree
Binary Tree
easy68%
Palindrome Linked List
Linked List
easy56%
Merge Two Sorted Lists
Linked List
medium52%
Remove Nth Node From End of List
Linked List
medium46%
Linked List Cycle II
Linked List
medium48%
Add Two Numbers
Linked List
medium45%
Validate Binary Search Tree
BSTBinary Tree
medium42%
Lowest Common Ancestor of a Binary Tree
Binary Tree
medium53%
Binary Tree Level Order Traversal
Binary Tree
medium55%
Binary Tree Zigzag Level Order Traversal
Binary Tree
medium46%
Path Sum II
Binary Tree
medium50%
Kth Smallest Element in a BST
BST
medium49%
Construct Binary Tree from Preorder and Inorder Traversal
Binary Tree
medium54%
Flatten Binary Tree to Linked List
Binary TreeLinked List
medium54%
Copy List with Random Pointer
Linked List
hard43%
Lowest Common Ancestor of a BST
BST
medium51%
Sort List
Linked List
hard40%
Binary Tree Right Side View
Binary Tree
medium52%
Swap Nodes in Pairs
Linked List
medium52%
Binary Tree Maximum Path Sum
Binary Tree
hard37%
Serialize and Deserialize Binary Tree
Binary Tree
hard44%
Reverse Nodes in k-Group
Linked List
hard43%
Binary Tree Cameras
Binary Tree
hard38%
Recover Binary Search Tree
BSTBinary Tree
hard40%
House Robber
Dynamic Programming
medium48%
Climbing Stairs
Dynamic Programming
easy62%
Longest Increasing Subsequence
Dynamic ProgrammingBinary Search
medium47%
Word Break
Dynamic Programming
medium45%
Edit Distance
Dynamic Programming
hard43%
Unique Paths
Dynamic Programming
medium55%
Jump Game
Dynamic Programming
medium43%
Decode Ways
Dynamic Programming
hard36%
Longest Common Subsequence
Dynamic Programming
medium51%
Coin Change
Dynamic Programming
medium43%
Palindrome Partitioning II
Dynamic Programming
hard36%
Burst Balloons
Dynamic Programming
hard43%
Regular Expression Matching
Dynamic Programming
hard36%
Longest Palindromic Subsequence
Dynamic Programming
medium51%
Maximum Product Subarray
Dynamic Programming
hard37%
Partition Equal Subset Sum
Dynamic Programming
medium47%
Wildcard Matching
Dynamic Programming
hard36%
Min Cost Climbing Stairs
Dynamic Programming
easy60%
Search in Rotated Sorted Array
Binary Search
medium42%
Find Peak Element
Binary Search
medium47%
Koko Eating Bananas
Binary Search
medium49%
Split Array Largest Sum
Binary SearchDynamic Programming
hard44%
Find Minimum in Rotated Sorted Array
Binary Search
medium48%
Search a 2D Matrix
Binary Search
easy57%
Capacity To Ship Packages Within D Days
Binary Search
medium54%
Find First and Last Position of Element in Sorted Array
Binary Search
easy56%
Interleaving String
Dynamic Programming
hard39%
Clone Graph
GraphsBFS+1
medium50%
Pacific Atlantic Water Flow
GraphsBFS+1
medium49%
Rotting Oranges
GraphsBFS
medium51%
Walls and Gates
GraphsBFS
medium53%
Shortest Path in Binary Matrix
GraphsBFS
medium44%
Open the Lock
GraphsBFS
hard41%
Network Delay Time
GraphsBFS
medium50%
Cheapest Flights Within K Stops
GraphsBFS+1
hard40%
Word Ladder
GraphsBFS
hard38%
Surrounded Regions
GraphsDFS+1
medium42%
Graph Valid Tree
GraphsUnion Find+1
medium46%
Number of Connected Components in an Undirected Graph
GraphsUnion Find+1
easy60%
Accounts Merge
GraphsUnion Find+1
medium49%
Redundant Connection
GraphsUnion Find
medium53%
Course Schedule
GraphsTopological Sort+1
medium47%
Course Schedule II
GraphsTopological Sort+1
medium46%
Reconstruct Itinerary
GraphsDFS
hard40%
Critical Connections in a Network
GraphsDFS
hard44%
Swim in Rising Water
GraphsBFS+1
hard43%
Find Eventual Safe States
GraphsDFS+1
easy58%
Alien Dictionary
GraphsTopological Sort
hard37%
Longest Increasing Path in a Matrix
GraphsDFS+1
hard42%
Min Stack
StackDesign
medium48%
Valid Parentheses
StackString
easy58%
Evaluate Reverse Polish Notation
StackMath
medium46%
Daily Temperatures
StackMonotonic Stack+1
medium50%
Next Greater Element I
StackMonotonic Stack+1
easy60%
Asteroid Collision
StackArray+1
medium47%
Decode String
StackString+1
medium49%
Online Stock Span
StackMonotonic Stack+1
medium52%
Basic Calculator
StackMath+1
hard38%
Largest Rectangle in Histogram
StackMonotonic Stack+1
hard40%
Trapping Rain Water
StackMonotonic Stack+1
hard43%
Implement Queue using Stacks
StackQueue+1
easy63%
Top K Frequent Elements
HeapHash Table+1
medium50%
Kth Largest Element in an Array
HeapSorting+1
medium48%
Merge K Sorted Lists
HeapLinked List+1
hard41%
Task Scheduler
HeapGreedy+1
medium44%
Reorganize String
HeapGreedy+1
medium42%
Find Median from Data Stream
HeapDesign+1
hard39%
Implement Trie (Prefix Tree)
TrieDesign+1
medium53%
Design Add and Search Words Data Structure
TrieDFS+2
hard40%
Word Search II
TrieBacktracking+1
hard37%
Map Sum Pairs
TrieHash Table+1
medium47%
Implement Stack using Queues
StackQueue+1
easy57%
Next Greater Element II
StackMonotonic Stack+1
medium48%
Subsets
BacktrackingArrays
medium54%
Permutations
BacktrackingArrays
medium53%
Combination Sum
BacktrackingArrays
medium51%
N-Queens
BacktrackingMatrix
hard44%
Letter Combinations of a Phone Number
BacktrackingStrings
medium48%
Palindrome Partitioning
BacktrackingStrings
hard42%
Generate Parentheses
BacktrackingStrings
medium52%
Sort Colors
SortingArrays+1
medium48%
Merge Sort - Count Inversions
SortingDivide and Conquer
hard38%
Meeting Rooms II
IntervalsSorting+1
medium45%
Non-overlapping Intervals
IntervalsGreedy+1
medium43%
Insert Interval
IntervalsArrays
hard36%
Single Number
Bit ManipulationArrays
easy67%
Counting Bits
Bit ManipulationDynamic Programming
easy65%
Reverse Bits
Bit Manipulation
easy55%
Number of 1 Bits
Bit Manipulation
easy62%
Power of Two
Bit ManipulationMath
medium43%
Missing Number
Bit ManipulationMath+1
medium44%
Gas Station
GreedyArrays
medium43%
Jump Game II
GreedyArrays
hard37%
Partition Labels
GreedyStrings+1
medium54%
Candy
GreedyArrays
hard36%
Merge Intervals
IntervalsSorting+1
hard41%

Browse 184 curated data structures and algorithms interview questions organized by topic and difficulty. Covers arrays, strings, linked lists, trees, graphs, dynamic programming, sorting, searching, and more — with structured solutions and complexity analysis.