Comprehensive DSA Sheet

405 problems across 18 topics. Filter by difficulty, company, or search for specific problems. All problems link directly to LeetCode.

DSA Sheet Progress0 / 405 (0%)

📊

Arrays

Array manipulation, sliding window, and prefix sums

#1Two Sum

EasySolve

ArrayHash TableGoogleAmazonMeta

#153Sum

MediumSolve

ArrayTwo PointersSortingGoogleAmazonMeta

#184Sum

MediumSolve

ArrayTwo PointersSortingAmazonMicrosoftGoldman Sachs

#31Next Permutation

MediumSolve

ArrayMathGoogleAmazonMicrosoft

#75Sort Colors

MediumSolve

ArrayTwo PointersSortingAmazonMicrosoftAdobe

#283Move Zeroes

EasySolve

ArrayTwo PointersMetaBloombergApple

#26Remove Duplicates from Sorted Array

EasySolve

ArrayTwo PointersAmazonMicrosoftBloomberg

#442Find All Duplicates in an Array

MediumSolve

ArrayHash TableAmazonMicrosoftGoogle

#41First Missing Positive

HardSolve

ArrayHash TableAmazonGoogleMicrosoft

#42Trapping Rain Water

HardSolve

ArrayTwo PointersStackGoogleAmazonGoldman Sachs

#53Maximum Subarray

MediumSolve

ArrayDynamic ProgrammingDivide and ConquerAmazonGoogleMicrosoft

#121Best Time to Buy and Sell Stock

EasySolve

ArrayDynamic ProgrammingAmazonGoogleMeta

#122Best Time to Buy and Sell Stock II

MediumSolve

ArrayGreedyAmazonBloombergGoldman Sachs

#123Best Time to Buy and Sell Stock III

HardSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#88Merge Sorted Array

EasySolve

ArrayTwo PointersSortingMetaMicrosoftAmazon

#189Rotate Array

MediumSolve

ArrayMathAmazonMicrosoftGoogle

#560Subarray Sum Equals K

MediumSolve

ArrayHash TableGoogleMetaAmazon

#169Majority Element

EasySolve

ArraySortingHash TableAmazonGoogleMicrosoft

#229Majority Element II

MediumSolve

ArrayHash TableSortingAmazonGoogleBloomberg

#55Jump Game

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleMicrosoft

#45Jump Game II

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleBloomberg

#134Gas Station

MediumSolve

ArrayGreedyAmazonGoogleBloomberg

#135Candy

HardSolve

ArrayGreedyGoogleAmazonBloomberg

#238Product of Array Except Self

MediumSolve

ArrayAmazonMetaApple

#162Find Peak Element

MediumSolve

ArrayBinary SearchGoogleMetaAmazon

#11Container With Most Water

MediumSolve

ArrayTwo PointersGreedyGoogleAmazonMeta

#84Largest Rectangle in Histogram

HardSolve

ArrayStackMonotonic StackGoogleAmazonMicrosoft

#209Minimum Size Subarray Sum

MediumSolve

ArrayBinary SearchSliding WindowAmazonGoogleGoldman Sachs

#54Spiral Matrix

MediumSolve

ArrayMatrixAmazonMicrosoftApple

#59Spiral Matrix II

MediumSolve

ArrayMatrixAmazonMicrosoftAdobe

#289Game of Life

MediumSolve

ArrayMatrixGoogleAmazonAtlassian

#118Pascal's Triangle

EasySolve

ArrayDynamic ProgrammingAmazonGoogleMicrosoft

#380Insert Delete GetRandom O(1)

MediumSolve

ArrayHash TableDesignMetaAmazonGoogle

#164Maximum Gap

MediumSolve

ArraySortingAmazonMicrosoftBloomberg

#274H-Index

MediumSolve

ArraySortingGoogleMetaBloomberg

#324Wiggle Sort II

MediumSolve

ArraySortingDivide and ConquerGoogleAmazonMicrosoft

🔤

Strings

String manipulation, pattern matching, and parsing

#125Valid Palindrome

EasySolve

StringTwo PointersMetaAmazonMicrosoft

#680Valid Palindrome II

EasySolve

StringTwo PointersGreedyMetaAmazonMicrosoft

#344Reverse String

EasySolve

StringTwo PointersAmazonMicrosoftApple

#3Longest Substring Without Repeating Characters

MediumSolve

StringHash TableSliding WindowAmazonGoogleMeta

#76Minimum Window Substring

HardSolve

StringHash TableSliding WindowGoogleMetaAmazon

#49Group Anagrams

MediumSolve

StringHash TableSortingAmazonGoogleMeta

#242Valid Anagram

EasySolve

StringHash TableSortingAmazonBloombergGoogle

#5Longest Palindromic Substring

MediumSolve

StringDynamic ProgrammingAmazonGoogleMicrosoft

#647Palindromic Substrings

MediumSolve

StringDynamic ProgrammingMetaGoogleAmazon

#424Longest Repeating Character Replacement

MediumSolve

StringHash TableSliding WindowGoogleAmazonMicrosoft

#8String to Integer (atoi)

MediumSolve

StringMathAmazonMicrosoftBloomberg

#38Count and Say

MediumSolve

StringMetaAmazonGoogle

#6Zigzag Conversion

MediumSolve

StringAmazonPayPalAdobe

#28Find the Index of the First Occurrence in a String

EasySolve

StringTwo PointersAmazonMicrosoftApple

#14Longest Common Prefix

EasySolve

StringAmazonGoogleAdobe

#43Multiply Strings

MediumSolve

StringMathGoogleMetaAmazon

#71Simplify Path

MediumSolve

StringStackMetaAmazonGoogle

#394Decode String

MediumSolve

StringStackRecursionGoogleAmazonBloomberg

#224Basic Calculator

HardSolve

StringStackMathGoogleAmazonMicrosoft

#227Basic Calculator II

MediumSolve

StringStackMathAmazonMetaMicrosoft

#68Text Justification

HardSolve

StringArrayGoogleAmazonLinkedIn

#12Integer to Roman

MediumSolve

StringMathAmazonMicrosoftBloomberg

#13Roman to Integer

EasySolve

StringMathAmazonMicrosoftBloomberg

#17Letter Combinations of a Phone Number

MediumSolve

StringBacktrackingAmazonGoogleMeta

#22Generate Parentheses

MediumSolve

StringBacktrackingAmazonGoogleMicrosoft

#290Word Pattern

EasySolve

StringHash TableAmazonMicrosoftUber

#205Isomorphic Strings

EasySolve

StringHash TableAmazonGoogleBloomberg

#187Repeated DNA Sequences

MediumSolve

StringHash TableBit ManipulationSliding WindowAmazonGoogleLinkedIn

#921Minimum Add to Make Parentheses Valid

MediumSolve

StringStackGreedyMetaAmazonGoogle

#20Valid Parentheses

EasySolve

StringStackAmazonGoogleMeta

🔗

Linked Lists

Singly and doubly linked list operations

#206Reverse Linked List

EasySolve

Linked ListRecursionAmazonMicrosoftGoogle

#92Reverse Linked List II

MediumSolve

Linked ListAmazonMicrosoftBloomberg

#141Linked List Cycle

EasySolve

Linked ListTwo PointersAmazonMicrosoftBloomberg

#142Linked List Cycle II

MediumSolve

Linked ListTwo PointersAmazonMicrosoftBloomberg

#21Merge Two Sorted Lists

EasySolve

Linked ListRecursionAmazonMicrosoftGoogle

#23Merge k Sorted Lists

HardSolve

Linked ListHeapDivide and ConquerAmazonGoogleMeta

#19Remove Nth Node From End of List

MediumSolve

Linked ListTwo PointersAmazonMetaGoogle

#83Remove Duplicates from Sorted List

EasySolve

Linked ListAmazonBloombergMicrosoft

#82Remove Duplicates from Sorted List II

MediumSolve

Linked ListTwo PointersAmazonBloombergMicrosoft

#2Add Two Numbers

MediumSolve

Linked ListMathAmazonGoogleMicrosoft

#445Add Two Numbers II

MediumSolve

Linked ListStackMathAmazonMicrosoftBloomberg

#160Intersection of Two Linked Lists

EasySolve

Linked ListTwo PointersAmazonMetaBloomberg

#234Palindrome Linked List

EasySolve

Linked ListTwo PointersStackAmazonMetaBloomberg

#328Odd Even Linked List

MediumSolve

Linked ListAmazonMicrosoftBloomberg

#148Sort List

MediumSolve

Linked ListSortingDivide and ConquerAmazonMicrosoftAdobe

#143Reorder List

MediumSolve

Linked ListTwo PointersStackAmazonMetaBloomberg

#61Rotate List

MediumSolve

Linked ListTwo PointersAmazonMicrosoftBloomberg

#24Swap Nodes in Pairs

MediumSolve

Linked ListRecursionAmazonMicrosoftBloomberg

#138Copy List with Random Pointer

MediumSolve

Linked ListHash TableAmazonMicrosoftBloomberg

#430Flatten a Multilevel Doubly Linked List

MediumSolve

Linked ListDFSMetaAmazonBloomberg

#146LRU Cache

MediumSolve

Linked ListHash TableDesignAmazonGoogleMeta

#86Partition List

MediumSolve

Linked ListTwo PointersAmazonMicrosoftBloomberg

#203Remove Linked List Elements

EasySolve

Linked ListRecursionAmazonMicrosoftBloomberg

#876Middle of the Linked List

EasySolve

Linked ListTwo PointersAmazonGoogleMicrosoft

#25Reverse Nodes in k-Group

HardSolve

Linked ListRecursionAmazonGoogleMicrosoft

📚

Stacks & Queues

Stack and queue based problem solving

#20Valid Parentheses

EasySolve

StringStackAmazonGoogleMeta

#155Min Stack

MediumSolve

StackDesignAmazonGoogleBloomberg

#232Implement Queue using Stacks

EasySolve

StackQueueDesignAmazonMicrosoftGoldman Sachs

#225Implement Stack using Queues

EasySolve

StackQueueDesignAmazonMicrosoftBloomberg

#739Daily Temperatures

MediumSolve

ArrayStackMonotonic StackAmazonGoogleMeta

#496Next Greater Element I

EasySolve

ArrayStackHash TableMonotonic StackAmazonBloombergGoogle

#503Next Greater Element II

MediumSolve

ArrayStackMonotonic StackAmazonBloombergGoogle

#84Largest Rectangle in Histogram

HardSolve

ArrayStackMonotonic StackGoogleAmazonMicrosoft

#42Trapping Rain Water

HardSolve

ArrayTwo PointersStackMonotonic StackGoogleAmazonGoldman Sachs

#150Evaluate Reverse Polish Notation

MediumSolve

ArrayStackMathAmazonGoogleLinkedIn

#224Basic Calculator

HardSolve

StringStackMathGoogleAmazonMicrosoft

#239Sliding Window Maximum

HardSolve

ArrayQueueSliding WindowHeapMonotonic StackAmazonGoogleMeta

#735Asteroid Collision

MediumSolve

ArrayStackAmazonGoogleBloomberg

#394Decode String

MediumSolve

StringStackRecursionGoogleAmazonBloomberg

#1209Remove All Adjacent Duplicates in String II

MediumSolve

StringStackBloombergAmazonGoogle

#901Online Stock Span

MediumSolve

StackDesignMonotonic StackAmazonBloombergMicrosoft

#895Maximum Frequency Stack

HardSolve

StackHash TableDesignAmazonGoogleBloomberg

#71Simplify Path

MediumSolve

StringStackMetaAmazonGoogle

#853Car Fleet

MediumSolve

ArrayStackSortingMonotonic StackGoogleAmazonBloomberg

#402Remove K Digits

MediumSolve

StringStackGreedyMonotonic StackAmazonGoogleMicrosoft

#946Validate Stack Sequences

MediumSolve

ArrayStackAmazonGoogleMicrosoft

#622Design Circular Queue

MediumSolve

ArrayQueueDesignAmazonGoogleMicrosoft

#641Design Circular Deque

MediumSolve

ArrayQueueDesignAmazonGoogleMicrosoft

#621Task Scheduler

MediumSolve

ArrayHash TableGreedySortingHeapMetaAmazonGoogle

#767Reorganize String

MediumSolve

StringHash TableGreedySortingHeapAmazonGoogleMeta

🌳

Trees

Binary trees, BSTs, and tree traversals

#104Maximum Depth of Binary Tree

EasySolve

Binary TreeDFSBFSAmazonGoogleMicrosoft

#100Same Tree

EasySolve

Binary TreeDFSBFSAmazonGoogleBloomberg

#226Invert Binary Tree

EasySolve

Binary TreeDFSBFSGoogleAmazonMeta

#101Symmetric Tree

EasySolve

Binary TreeDFSBFSAmazonMicrosoftBloomberg

#102Binary Tree Level Order Traversal

MediumSolve

Binary TreeBFSAmazonMicrosoftMeta

#103Binary Tree Zigzag Level Order Traversal

MediumSolve

Binary TreeBFSAmazonMicrosoftBloomberg

#199Binary Tree Right Side View

MediumSolve

Binary TreeDFSBFSMetaAmazonBloomberg

#222Count Complete Tree Nodes

EasySolve

Binary TreeBinary SearchDFSGoogleAmazonMicrosoft

#110Balanced Binary Tree

EasySolve

Binary TreeDFSAmazonGoogleBloomberg

#112Path Sum

EasySolve

Binary TreeDFSBFSAmazonMicrosoftBloomberg

#113Path Sum II

MediumSolve

Binary TreeDFSBacktrackingAmazonMicrosoftBloomberg

#124Binary Tree Maximum Path Sum

HardSolve

Binary TreeDFSDynamic ProgrammingGoogleAmazonMeta

#236Lowest Common Ancestor of a Binary Tree

MediumSolve

Binary TreeDFSAmazonGoogleMeta

#235Lowest Common Ancestor of a Binary Search Tree

MediumSolve

Binary TreeBSTDFSAmazonMetaMicrosoft

#98Validate Binary Search Tree

MediumSolve

Binary TreeBSTDFSAmazonGoogleMeta

#230Kth Smallest Element in a BST

MediumSolve

Binary TreeBSTDFSAmazonGoogleBloomberg

#94Binary Tree Inorder Traversal

EasySolve

Binary TreeStackDFSAmazonMicrosoftGoogle

#144Binary Tree Preorder Traversal

EasySolve

Binary TreeStackDFSAmazonMicrosoftGoogle

#145Binary Tree Postorder Traversal

EasySolve

Binary TreeStackDFSAmazonMicrosoftGoogle

#105Construct Binary Tree from Preorder and Inorder Traversal

MediumSolve

Binary TreeArrayDFSDivide and ConquerAmazonMicrosoftGoogle

#297Serialize and Deserialize Binary Tree

HardSolve

Binary TreeDFSBFSDesignAmazonGoogleMeta

#114Flatten Binary Tree to Linked List

MediumSolve

Binary TreeDFSLinked ListStackAmazonMicrosoftBloomberg

#543Diameter of Binary Tree

EasySolve

Binary TreeDFSMetaAmazonGoogle

#572Subtree of Another Tree

EasySolve

Binary TreeDFSAmazonGoogleMeta

#129Sum Root to Leaf Numbers

MediumSolve

Binary TreeDFSAmazonMicrosoftBloomberg

#116Populating Next Right Pointers in Each Node

MediumSolve

Binary TreeBFSDFSAmazonMicrosoftBloomberg

#337House Robber III

MediumSolve

Binary TreeDFSDynamic ProgrammingAmazonGoogleUber

#96Unique Binary Search Trees

MediumSolve

Binary TreeBSTDynamic ProgrammingMathAmazonGoogleMicrosoft

#95Unique Binary Search Trees II

MediumSolve

Binary TreeBSTDynamic ProgrammingBacktrackingAmazonGoogleBloomberg

#99Recover Binary Search Tree

MediumSolve

Binary TreeBSTDFSAmazonMicrosoftBloomberg

#968Binary Tree Cameras

HardSolve

Binary TreeDFSDynamic ProgrammingGreedyAmazonGoogleMicrosoft

#814Binary Tree Pruning

MediumSolve

Binary TreeDFSAmazonBloombergGoogle

#662Maximum Width of Binary Tree

MediumSolve

Binary TreeBFSDFSAmazonGoogleBloomberg

#987Vertical Order Traversal of a Binary Tree

HardSolve

Binary TreeBFSDFSHash TableSortingMetaAmazonGoogle

#429N-ary Tree Level Order Traversal

MediumSolve

Binary TreeBFSAmazonMicrosoftGoogle

#538Convert BST to Greater Tree

MediumSolve

Binary TreeBSTDFSAmazonGoogleBloomberg

🕸️

Graphs

Graph traversal, shortest paths, and connectivity

#200Number of Islands

MediumSolve

ArrayDFSBFSUnion FindMatrixAmazonGoogleMeta

#133Clone Graph

MediumSolve

GraphDFSBFSHash TableAmazonGoogleMeta

#207Course Schedule

MediumSolve

GraphDFSBFSAmazonGoogleMicrosoft

#210Course Schedule II

MediumSolve

GraphDFSBFSAmazonGoogleMicrosoft

#417Pacific Atlantic Water Flow

MediumSolve

ArrayDFSBFSMatrixGoogleAmazonBloomberg

#128Longest Consecutive Sequence

MediumSolve

ArrayHash TableUnion FindGoogleAmazonMeta

#127Word Ladder

HardSolve

StringBFSHash TableAmazonGoogleMeta

#126Word Ladder II

HardSolve

StringBFSHash TableBacktrackingAmazonGoogleMeta

#130Surrounded Regions

MediumSolve

ArrayDFSBFSUnion FindMatrixAmazonGoogleBloomberg

#743Network Delay Time

MediumSolve

GraphDFSBFSHeapAmazonGoogleMicrosoft

#787Cheapest Flights Within K Stops

MediumSolve

GraphDynamic ProgrammingBFSHeapAmazonGoogleBloomberg

#684Redundant Connection

MediumSolve

GraphUnion FindDFSBFSAmazonGoogleMicrosoft

#1192Critical Connections in a Network

HardSolve

GraphDFSAmazonGoogleMicrosoft

#721Accounts Merge

MediumSolve

ArrayStringDFSBFSUnion FindMetaAmazonGoogle

#399Evaluate Division

MediumSolve

ArrayDFSBFSUnion FindGraphGoogleAmazonBloomberg

#994Rotting Oranges

MediumSolve

ArrayBFSMatrixAmazonGoogleMicrosoft

#1091Shortest Path in Binary Matrix

MediumSolve

ArrayBFSMatrixAmazonMetaGoogle

#785Is Graph Bipartite?

MediumSolve

GraphDFSBFSUnion FindAmazonGoogleMeta

#269Alien DictionaryPremium

HardSolve

ArrayStringGraphDFSBFSAmazonGoogleMeta

#332Reconstruct Itinerary

HardSolve

GraphDFSSortingGoogleAmazonBloomberg

#797All Paths From Source to Target

MediumSolve

GraphDFSBFSBacktrackingAmazonGoogleBloomberg

#841Keys and Rooms

MediumSolve

GraphDFSBFSAmazonGoogleBloomberg

#1971Find if Path Exists in Graph

EasySolve

GraphDFSBFSUnion FindAmazonGoogleMicrosoft

#310Minimum Height Trees

MediumSolve

GraphDFSBFSAmazonGoogleMicrosoft

#909Snakes and Ladders

MediumSolve

ArrayBFSMatrixAmazonGoogleGoldman Sachs

#752Open the Lock

MediumSolve

ArrayBFSHash TableStringAmazonGoogleByteDance

#778Swim in Rising Water

HardSolve

ArrayGraphBFSDFSHeapUnion FindMatrixGoogleAmazonBloomberg

#827Making A Large Island

HardSolve

ArrayDFSBFSUnion FindMatrixAmazonGoogleMeta

#547Number of Provinces

MediumSolve

GraphDFSBFSUnion FindAmazonGoogleBloomberg

#997Find the Town Judge

EasySolve

ArrayGraphHash TableAmazonGoogleBloomberg

#934Shortest Bridge

MediumSolve

ArrayDFSBFSMatrixAmazonGoogleMicrosoft

#261Graph Valid TreePremium

MediumSolve

GraphDFSBFSUnion FindAmazonGoogleMeta

#323Number of Connected Components in an Undirected GraphPremium

MediumSolve

GraphDFSBFSUnion FindAmazonGoogleMeta

#212Word Search II

HardSolve

ArrayStringBacktrackingTrieMatrixAmazonGoogleMicrosoft

⛰️

Heaps

Priority queues and heap-based algorithms

#215Kth Largest Element in an Array

MediumSolve

ArrayHeapSortingDivide and ConquerAmazonGoogleMeta

#347Top K Frequent Elements

MediumSolve

ArrayHash TableHeapSortingAmazonGoogleMeta

#295Find Median from Data Stream

HardSolve

HeapDesignSortingAmazonGoogleMicrosoft

#23Merge k Sorted Lists

HardSolve

Linked ListHeapDivide and ConquerAmazonGoogleMeta

#451Sort Characters By Frequency

MediumSolve

StringHash TableHeapSortingAmazonGoogleBloomberg

#378Kth Smallest Element in a Sorted Matrix

MediumSolve

ArrayHeapBinary SearchMatrixSortingAmazonGoogleMeta

#253Meeting Rooms IIPremium

MediumSolve

ArrayHeapSortingIntervalAmazonGoogleMeta

#621Task Scheduler

MediumSolve

ArrayHash TableGreedySortingHeapMetaAmazonGoogle

#767Reorganize String

MediumSolve

StringHash TableGreedySortingHeapAmazonGoogleMeta

#973K Closest Points to Origin

MediumSolve

ArrayHeapMathSortingDivide and ConquerAmazonMetaGoogle

#1046Last Stone Weight

EasySolve

ArrayHeapAmazonGoogleBloomberg

#703Kth Largest Element in a Stream

EasySolve

HeapDesignBinary SearchAmazonGoogleMeta

#264Ugly Number II

MediumSolve

Hash TableMathHeapDynamic ProgrammingAmazonGoogleBloomberg

#313Super Ugly Number

MediumSolve

ArrayMathHeapDynamic ProgrammingAmazonGoogleBloomberg

#502IPO

HardSolve

ArrayGreedySortingHeapAmazonGoogleGoldman Sachs

🔡

Tries

Prefix trees and string search structures

#208Implement Trie Prefix Tree

MediumSolve

TrieStringHash TableDesignAmazonGoogleMicrosoft

#211Design Add and Search Words Data Structure

MediumSolve

TrieStringDFSDesignAmazonGoogleMeta

#212Word Search II

HardSolve

ArrayStringBacktrackingTrieMatrixAmazonGoogleMicrosoft

#648Replace Words

MediumSolve

ArrayStringTrieHash TableAmazonUberGoogle

#720Longest Word in Dictionary

MediumSolve

ArrayStringTrieHash TableSortingAmazonGoogleBloomberg

#677Map Sum Pairs

MediumSolve

TrieStringHash TableDesignAmazonGoogleBloomberg

#421Maximum XOR of Two Numbers in an Array

MediumSolve

ArrayTrieHash TableBit ManipulationAmazonGoogleMicrosoft

#336Palindrome Pairs

HardSolve

ArrayStringTrieHash TableAmazonGoogleAirbnb

#642Design Search Autocomplete SystemPremium

HardSolve

StringTrieDesignSortingHeapHash TableAmazonGoogleMicrosoft

#1032Stream of Characters

HardSolve

ArrayStringTrieDesignGoogleAmazonBloomberg

📈

Dynamic Programming

Optimal substructure and overlapping subproblems

#70Climbing Stairs

EasySolve

MathDynamic ProgrammingAmazonGoogleMicrosoft

#198House Robber

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleMicrosoft

#213House Robber II

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#337House Robber III

MediumSolve

Binary TreeDFSDynamic ProgrammingAmazonGoogleUber

#322Coin Change

MediumSolve

ArrayDynamic ProgrammingBFSAmazonGoogleMicrosoft

#518Coin Change II

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#300Longest Increasing Subsequence

MediumSolve

ArrayBinary SearchDynamic ProgrammingAmazonGoogleMicrosoft

#1143Longest Common Subsequence

MediumSolve

StringDynamic ProgrammingAmazonGoogleMicrosoft

#72Edit Distance

MediumSolve

StringDynamic ProgrammingAmazonGoogleMicrosoft

#139Word Break

MediumSolve

ArrayStringHash TableDynamic ProgrammingAmazonGoogleMeta

#140Word Break II

HardSolve

ArrayStringHash TableDynamic ProgrammingBacktrackingAmazonGoogleMeta

#55Jump Game

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleMicrosoft

#45Jump Game II

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleBloomberg

#91Decode Ways

MediumSolve

StringDynamic ProgrammingAmazonGoogleMeta

#62Unique Paths

MediumSolve

MathDynamic ProgrammingAmazonGoogleMicrosoft

#63Unique Paths II

MediumSolve

ArrayDynamic ProgrammingMatrixAmazonGoogleBloomberg

#64Minimum Path Sum

MediumSolve

ArrayDynamic ProgrammingMatrixAmazonGoogleGoldman Sachs

#120Triangle

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleMicrosoft

#221Maximal Square

MediumSolve

ArrayDynamic ProgrammingMatrixAmazonGoogleApple

#131Palindrome Partitioning

MediumSolve

StringDynamic ProgrammingBacktrackingAmazonGoogleBloomberg

#132Palindrome Partitioning II

HardSolve

StringDynamic ProgrammingAmazonGoogleBloomberg

#97Interleaving String

MediumSolve

StringDynamic ProgrammingAmazonGoogleMicrosoft

#10Regular Expression Matching

HardSolve

StringDynamic ProgrammingRecursionGoogleAmazonMeta

#44Wildcard Matching

HardSolve

StringDynamic ProgrammingGreedyGoogleAmazonBloomberg

#309Best Time to Buy and Sell Stock with Cooldown

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleGoldman Sachs

#714Best Time to Buy and Sell Stock with Transaction Fee

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleBloomberg

#494Target Sum

MediumSolve

ArrayDynamic ProgrammingBacktrackingAmazonGoogleMeta

#416Partition Equal Subset Sum

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleMeta

#516Longest Palindromic Subsequence

MediumSolve

StringDynamic ProgrammingAmazonGoogleLinkedIn

#115Distinct Subsequences

HardSolve

StringDynamic ProgrammingAmazonGoogleBloomberg

#312Burst Balloons

HardSolve

ArrayDynamic ProgrammingAmazonGoogleMicrosoft

#1130Minimum Cost Tree From Leaf Values

MediumSolve

ArrayDynamic ProgrammingStackGreedyMonotonic StackAmazonGoogleBloomberg

#877Stone Game

MediumSolve

ArrayMathDynamic ProgrammingAmazonGoogleBloomberg

#279Perfect Squares

MediumSolve

MathDynamic ProgrammingBFSAmazonGoogleBloomberg

#264Ugly Number II

MediumSolve

Hash TableMathHeapDynamic ProgrammingAmazonGoogleBloomberg

#152Maximum Product Subarray

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleMicrosoft

#174Dungeon Game

HardSolve

ArrayDynamic ProgrammingMatrixAmazonGoogleMicrosoft

#741Cherry Pickup

HardSolve

ArrayDynamic ProgrammingMatrixGoogleAmazonBloomberg

#413Arithmetic Slices

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#377Combination Sum IV

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#474Ones and Zeroes

MediumSolve

ArrayStringDynamic ProgrammingAmazonGoogleBloomberg

#879Profitable Schemes

HardSolve

ArrayDynamic ProgrammingGoogleAmazonBloomberg

#983Minimum Cost For Tickets

MediumSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#1048Longest String Chain

MediumSolve

ArrayStringHash TableDynamic ProgrammingAmazonGoogleMeta

#403Frog Jump

HardSolve

ArrayDynamic ProgrammingAmazonGoogleMicrosoft

#1335Minimum Difficulty of a Job Schedule

HardSolve

ArrayDynamic ProgrammingAmazonGoogleBloomberg

#740Delete and Earn

MediumSolve

ArrayHash TableDynamic ProgrammingAmazonGoogleBloomberg

#639Decode Ways II

HardSolve

StringDynamic ProgrammingAmazonGoogleMeta

#673Number of Longest Increasing Subsequence

MediumSolve

ArrayDynamic ProgrammingBinary SearchAmazonGoogleBloomberg

#354Russian Doll Envelopes

HardSolve

ArrayBinary SearchDynamic ProgrammingSortingAmazonGoogleMicrosoft

#368Largest Divisible Subset

MediumSolve

ArrayMathDynamic ProgrammingSortingAmazonGoogleBloomberg

#730Count Different Palindromic Subsequences

HardSolve

StringDynamic ProgrammingAmazonGoogleLinkedIn

#712Minimum ASCII Delete Sum for Two Strings

MediumSolve

StringDynamic ProgrammingAmazonGoogleBloomberg

#486Predict the Winner

MediumSolve

ArrayMathDynamic ProgrammingRecursionAmazonGoogleBloomberg

🔙

Backtracking

Exhaustive search with pruning

#78Subsets

MediumSolve

ArrayBacktrackingBit ManipulationAmazonGoogleMeta

#90Subsets II

MediumSolve

ArrayBacktrackingBit ManipulationAmazonGoogleBloomberg

#46Permutations

MediumSolve

ArrayBacktrackingAmazonGoogleMeta

#47Permutations II

MediumSolve

ArrayBacktrackingAmazonGoogleBloomberg

#39Combination Sum

MediumSolve

ArrayBacktrackingAmazonGoogleMeta

#40Combination Sum II

MediumSolve

ArrayBacktrackingAmazonGoogleBloomberg

#216Combination Sum III

MediumSolve

ArrayBacktrackingAmazonMicrosoftGoogle

#77Combinations

MediumSolve

ArrayBacktrackingAmazonGoogleMicrosoft

#17Letter Combinations of a Phone Number

MediumSolve

StringBacktrackingHash TableAmazonGoogleMeta

#22Generate Parentheses

MediumSolve

StringBacktrackingDynamic ProgrammingAmazonGoogleMicrosoft

#131Palindrome Partitioning

MediumSolve

StringDynamic ProgrammingBacktrackingAmazonGoogleBloomberg

#51N-Queens

HardSolve

ArrayBacktrackingAmazonGoogleMicrosoft

#52N-Queens II

HardSolve

ArrayBacktrackingAmazonGoogleMicrosoft

#37Sudoku Solver

HardSolve

ArrayBacktrackingMatrixAmazonGoogleMicrosoft

#79Word Search

MediumSolve

ArrayBacktrackingMatrixAmazonGoogleMicrosoft

#93Restore IP Addresses

MediumSolve

StringBacktrackingAmazonGoogleBloomberg

#698Partition to K Equal Sum Subsets

MediumSolve

ArrayBacktrackingDynamic ProgrammingBit ManipulationAmazonGoogleLinkedIn

#282Expression Add Operators

HardSolve

StringMathBacktrackingGoogleMetaAmazon

#526Beautiful Arrangement

MediumSolve

ArrayBacktrackingDynamic ProgrammingBit ManipulationAmazonGoogleBloomberg

#1849Splitting a String Into Descending Consecutive Values

MediumSolve

StringBacktrackingAmazonGoogleBloomberg

🎯

Greedy

Locally optimal choices for global solutions

#55Jump Game

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleMicrosoft

#45Jump Game II

MediumSolve

ArrayDynamic ProgrammingGreedyAmazonGoogleBloomberg

#134Gas Station

MediumSolve

ArrayGreedyAmazonGoogleBloomberg

#135Candy

HardSolve

ArrayGreedyGoogleAmazonBloomberg

#621Task Scheduler

MediumSolve

ArrayHash TableGreedySortingHeapMetaAmazonGoogle

#406Queue Reconstruction by Height

MediumSolve

ArrayGreedySortingAmazonGoogleMicrosoft

#435Non-overlapping Intervals

MediumSolve

ArrayGreedySortingDynamic ProgrammingIntervalAmazonGoogleMeta

#452Minimum Number of Arrows to Burst Balloons

MediumSolve

ArrayGreedySortingIntervalAmazonGoogleMeta

#455Assign Cookies

EasySolve

ArrayGreedySortingTwo PointersAmazonBloombergGoogle

#763Partition Labels

MediumSolve

ArrayStringHash TableGreedyTwo PointersAmazonGoogleBloomberg

#860Lemonade Change

EasySolve

ArrayGreedyAmazonGoogleBloomberg

#252Meeting RoomsPremium

EasySolve

ArraySortingIntervalAmazonGoogleMeta

#881Boats to Save People

MediumSolve

ArrayGreedyTwo PointersSortingAmazonGoogleMicrosoft

#948Bag of Tokens

MediumSolve

ArrayGreedyTwo PointersSortingAmazonGoogleBloomberg

#1029Two City Scheduling

MediumSolve

ArrayGreedySortingAmazonBloombergGoldman Sachs

#991Broken Calculator

MediumSolve

MathGreedyAmazonGoogleBloomberg

#1007Minimum Domino Rotations For Equal Row

MediumSolve

ArrayGreedyGoogleAmazonBloomberg

#659Split Array into Consecutive Subsequences

MediumSolve

ArrayHash TableGreedyHeapGoogleAmazonBloomberg

#870Advantage Shuffle

MediumSolve

ArrayGreedySortingTwo PointersAmazonGoogleBloomberg

#986Interval List Intersections

MediumSolve

ArrayTwo PointersIntervalMetaAmazonGoogle

🔍

Binary Search

Divide and conquer search on sorted data

#704Binary Search

EasySolve

ArrayBinary SearchAmazonGoogleMicrosoft

#33Search in Rotated Sorted Array

MediumSolve

ArrayBinary SearchAmazonGoogleMeta

#81Search in Rotated Sorted Array II

MediumSolve

ArrayBinary SearchAmazonGoogleBloomberg

#153Find Minimum in Rotated Sorted Array

MediumSolve

ArrayBinary SearchAmazonGoogleMicrosoft

#154Find Minimum in Rotated Sorted Array II

HardSolve

ArrayBinary SearchAmazonGoogleBloomberg

#74Search a 2D Matrix

MediumSolve

ArrayBinary SearchMatrixAmazonGoogleMicrosoft

#240Search a 2D Matrix II

MediumSolve

ArrayBinary SearchMatrixDivide and ConquerAmazonGoogleMicrosoft

#162Find Peak Element

MediumSolve

ArrayBinary SearchGoogleMetaAmazon

#34Find First and Last Position of Element in Sorted Array

MediumSolve

ArrayBinary SearchAmazonGoogleMeta

#69Sqrt(x)

EasySolve

MathBinary SearchAmazonGoogleBloomberg

#875Koko Eating Bananas

MediumSolve

ArrayBinary SearchAmazonGoogleBloomberg

#1011Capacity To Ship Packages Within D Days

MediumSolve

ArrayBinary SearchAmazonGoogleMicrosoft

#410Split Array Largest Sum

HardSolve

ArrayBinary SearchDynamic ProgrammingGreedyAmazonGoogleBloomberg

#4Median of Two Sorted Arrays

HardSolve

ArrayBinary SearchDivide and ConquerAmazonGoogleMicrosoft

#1552Magnetic Force Between Two Balls

MediumSolve

ArrayBinary SearchSortingAmazonGoogleBloomberg

#1870Minimum Speed to Arrive on Time

MediumSolve

ArrayBinary SearchAmazonGoogleBloomberg

#327Count of Range Sum

HardSolve

ArrayBinary SearchDivide and ConquerSortingGoogleAmazonBloomberg

#1044Longest Duplicate Substring

HardSolve

StringBinary SearchHash TableSliding WindowAmazonGoogleBloomberg

#528Random Pick with Weight

MediumSolve

ArrayMathBinary SearchMetaGoogleAmazon

#981Time Based Key-Value Store

MediumSolve

StringBinary SearchHash TableDesignAmazonGoogleMeta

👆

Two Pointers

Two pointer and sliding window techniques

#167Two Sum II - Input Array Is Sorted

MediumSolve

ArrayTwo PointersBinary SearchAmazonGoogleBloomberg

#153Sum

MediumSolve

ArrayTwo PointersSortingGoogleAmazonMeta

#163Sum Closest

MediumSolve

ArrayTwo PointersSortingAmazonGoogleBloomberg

#184Sum

MediumSolve

ArrayTwo PointersSortingAmazonMicrosoftGoldman Sachs

#11Container With Most Water

MediumSolve

ArrayTwo PointersGreedyGoogleAmazonMeta

#42Trapping Rain Water

HardSolve

ArrayTwo PointersStackMonotonic StackGoogleAmazonGoldman Sachs

#26Remove Duplicates from Sorted Array

EasySolve

ArrayTwo PointersAmazonMicrosoftBloomberg

#80Remove Duplicates from Sorted Array II

MediumSolve

ArrayTwo PointersAmazonMicrosoftBloomberg

#283Move Zeroes

EasySolve

ArrayTwo PointersMetaBloombergApple

#75Sort Colors

MediumSolve

ArrayTwo PointersSortingAmazonMicrosoftAdobe

#977Squares of a Sorted Array

EasySolve

ArrayTwo PointersSortingAmazonGoogleMeta

#881Boats to Save People

MediumSolve

ArrayTwo PointersGreedySortingAmazonGoogleMicrosoft

#986Interval List Intersections

MediumSolve

ArrayTwo PointersIntervalMetaAmazonGoogle

#844Backspace String Compare

EasySolve

StringTwo PointersStackGoogleAmazonBloomberg

#925Long Pressed Name

EasySolve

StringTwo PointersGoogleAmazonBloomberg

#845Longest Mountain in Array

MediumSolve

ArrayTwo PointersDynamic ProgrammingAmazonGoogleBloomberg

#125Valid Palindrome

EasySolve

StringTwo PointersMetaAmazonMicrosoft

#680Valid Palindrome II

EasySolve

StringTwo PointersGreedyMetaAmazonMicrosoft

#344Reverse String

EasySolve

StringTwo PointersAmazonMicrosoftApple

#88Merge Sorted Array

EasySolve

ArrayTwo PointersSortingMetaMicrosoftAmazon

💡

Bit Manipulation

Bitwise operations and binary representations

#136Single Number

EasySolve

ArrayBit ManipulationAmazonGoogleBloomberg

#137Single Number II

MediumSolve

ArrayBit ManipulationAmazonGoogleBloomberg

#260Single Number III

MediumSolve

ArrayBit ManipulationAmazonGoogleBloomberg

#191Number of 1 Bits

EasySolve

Bit ManipulationDivide and ConquerAmazonMicrosoftApple

#338Counting Bits

EasySolve

Bit ManipulationDynamic ProgrammingAmazonGoogleMicrosoft

#190Reverse Bits

EasySolve

Bit ManipulationDivide and ConquerAmazonAppleGoogle

#268Missing Number

EasySolve

ArrayBit ManipulationMathHash TableSortingAmazonMicrosoftBloomberg

#371Sum of Two Integers

MediumSolve

Bit ManipulationMathAmazonGoogleMeta

#231Power of Two

EasySolve

Bit ManipulationMathAmazonGoogleApple

#201Bitwise AND of Numbers Range

MediumSolve

Bit ManipulationAmazonMicrosoftBloomberg

#393UTF-8 Validation

MediumSolve

ArrayBit ManipulationGoogleMetaAmazon

#477Total Hamming Distance

MediumSolve

ArrayBit ManipulationMathAmazonMetaGoogle

#421Maximum XOR of Two Numbers in an Array

MediumSolve

ArrayTrieHash TableBit ManipulationAmazonGoogleMicrosoft

#89Gray Code

MediumSolve

Bit ManipulationMathBacktrackingAmazonMicrosoftBloomberg

#29Divide Two Integers

MediumSolve

Bit ManipulationMathAmazonMetaBloomberg

🔢

Math

Mathematical algorithms and number theory

#7Reverse Integer

MediumSolve

MathAmazonBloombergApple

#9Palindrome Number

EasySolve

MathAmazonBloombergAdobe

#50Pow(x, n)

MediumSolve

MathRecursionAmazonGoogleMeta

#69Sqrt(x)

EasySolve

MathBinary SearchAmazonGoogleBloomberg

#202Happy Number

EasySolve

Hash TableMathTwo PointersAmazonGoogleBloomberg

#66Plus One

EasySolve

ArrayMathAmazonGoogleBloomberg

#172Factorial Trailing Zeroes

MediumSolve

MathAmazonBloombergMicrosoft

#168Excel Sheet Column Title

EasySolve

MathStringAmazonMicrosoftBloomberg

#171Excel Sheet Column Number

EasySolve

MathStringAmazonMicrosoftBloomberg

#204Count Primes

MediumSolve

ArrayMathAmazonMicrosoftBloomberg

#13Roman to Integer

EasySolve

StringMathAmazonMicrosoftBloomberg

#12Integer to Roman

MediumSolve

StringMathAmazonMicrosoftBloomberg

#1071Greatest Common Divisor of Strings

EasySolve

StringMathAmazonGoogleBloomberg

#412Fizz Buzz

EasySolve

MathStringAmazonMicrosoftBloomberg

#67Add Binary

EasySolve

MathStringBit ManipulationAmazonMetaGoogle

🏗️

Design

Data structure and system design problems

#146LRU Cache

MediumSolve

Linked ListHash TableDesignAmazonGoogleMeta

#460LFU Cache

HardSolve

Hash TableLinked ListDesignAmazonGoogleBloomberg

#155Min Stack

MediumSolve

StackDesignAmazonGoogleBloomberg

#232Implement Queue using Stacks

EasySolve

StackQueueDesignAmazonMicrosoftGoldman Sachs

#706Design HashMap

EasySolve

ArrayHash TableDesignAmazonGoogleMicrosoft

#705Design HashSet

EasySolve

ArrayHash TableDesignAmazonGoogleMicrosoft

#380Insert Delete GetRandom O(1)

MediumSolve

ArrayHash TableDesignMetaAmazonGoogle

#297Serialize and Deserialize Binary Tree

HardSolve

Binary TreeDFSBFSDesignAmazonGoogleMeta

#355Design Twitter

MediumSolve

Hash TableHeapDesignLinked ListAmazonGoogleBloomberg

#622Design Circular Queue

MediumSolve

ArrayQueueDesignAmazonGoogleMicrosoft

#208Implement Trie Prefix Tree

MediumSolve

TrieStringHash TableDesignAmazonGoogleMicrosoft

#211Design Add and Search Words Data Structure

MediumSolve

TrieStringDFSDesignAmazonGoogleMeta

#901Online Stock Span

MediumSolve

StackDesignMonotonic StackAmazonBloombergMicrosoft

#1472Design Browser History

MediumSolve

ArrayStackDesignLinked ListAmazonBloombergGoogle

#1396Design Underground System

MediumSolve

Hash TableStringDesignAmazonBloombergGoogle

📋

Sorting

Sorting algorithms and order-based problems

#75Sort Colors

MediumSolve

ArrayTwo PointersSortingAmazonMicrosoftAdobe

#148Sort List

MediumSolve

Linked ListSortingDivide and ConquerAmazonMicrosoftAdobe

#179Largest Number

MediumSolve

ArrayStringGreedySortingAmazonGoogleBloomberg

#56Merge Intervals

MediumSolve

ArraySortingIntervalAmazonGoogleMeta

#57Insert Interval

MediumSolve

ArraySortingIntervalAmazonGoogleMeta

#252Meeting RoomsPremium

EasySolve

ArraySortingIntervalAmazonGoogleMeta

#253Meeting Rooms IIPremium

MediumSolve

ArraySortingHeapIntervalAmazonGoogleMeta

#274H-Index

MediumSolve

ArraySortingGoogleMetaBloomberg

#324Wiggle Sort II

MediumSolve

ArraySortingDivide and ConquerGoogleAmazonMicrosoft

#164Maximum Gap

MediumSolve

ArraySortingAmazonMicrosoftBloomberg

#215Kth Largest Element in an Array

MediumSolve

ArrayHeapSortingDivide and ConquerAmazonGoogleMeta

#451Sort Characters By Frequency

MediumSolve

StringHash TableHeapSortingAmazonGoogleBloomberg

#1122Relative Sort Array

EasySolve

ArrayHash TableSortingAmazonGoogleBloomberg

#791Custom Sort String

MediumSolve

StringHash TableSortingMetaAmazonGoogle

#347Top K Frequent Elements

MediumSolve

ArrayHash TableHeapSortingAmazonGoogleMeta