Curated lists of Leetcode questions group by companies, updated as of May, 2022.
Shout out to fishercoder1534 for the awesome Leetcode repo for solutions.
- APT Portfolio
- Accenture
- Activision
- Adobe
- Affirm
- Airbnb
- Akamai
- Akuna Capital
- Alation
- Alibaba
- AllinCall
- Amazon
- American Express
- Apple
- Arcesium
- Arista Networks
- Asana
- Athenahealth
- Atlassian
- Baidu
- Barclays
- BlackRock
- Bloomberg
- Bolt
- Booking
- Box
- ByteDance
- C3 IoT
- Canonical
- Capital One
- Cashfree
- Cisco
- Citadel
- Citrix
- Cohesity
- Commvault
- Coursera
- Cruise Automation
- DE Shaw
- DJI
- DRW
- Databricks
- Dataminr
- Dell
- Deutsche Bank
- Directi
- Docusign
- DoorDash
- Drawbridge
- Dropbox
- Druva
- Dunzo
- Duolingo
- Epic Systems
- Expedia
- FPT
- FactSet
- Flipkart
- Gilt Groupe
- GoDaddy
- Goldman Sachs
- Grab
- HBO
- HRT
- Honeywell
- Hotstar
- Huawei
- Hulu
- IBM
- IIT Bombay
- IMC
- IXL
- Indeed
- Info Edge
- Infosys
- Intel
- Intuit
- JPMorgan
- Jane Street
- Jeavio
- Karat
- Leap Motion
- LiveRamp
- Lyft
- MAQ Software
- MakeMyTrip
- Mathworks
- Mercari
- Microsoft
- MindTickle
- MindTree
- Moengage
- Morgan Stanley
- National Instruments
- Netflix
- Netsuite
- Nuro
- Nutanix
- Nvidia
- OT
- Opendoor
- Optum
- Oracle
- Palantir Technologies
- PayTM
- Paypal
- PhonePe
- Pocket Gems
- Postmates
- Pure Storage
- Qualcomm
- Qualtrics
- Quora
- Rakuten
- Redfin
- Riot Games
- Robinhood
- Roblox
- Rubrik
- Rupeek
- SAP
- Salesforce
- Samsung
- Sapient
- ServiceNow
- Shopee
- Snapchat
- Softwire
- Sony
- Splunk
- Spotify
- Sprinklr
- Square
- Sumologic
- Swiggy
- T System
- TIAA
- Tencent
- Tesla
- Thumbtack
- Tiger Analytics
- Toptal
- TripleByte
- TuSimple
- Twilio
- Twitch
- Two Sigma
- Uber
- United Health Group
- VMware
- Valve
- Virtu Financial
- Visa
- Walmart Global Tech
- Wayfair
- Wealthfront
- Wish
- Works Applications
- Yahoo
- Yandex
- Yelp
- ZScaler
- Zenefits
- Zillow
- Zoho
- Zomato
- Zoom
- Zopsmart
- eBay
- edabit
- instacart
- payu
- peak6
- persistent systems
- razorpay
- tcs
- tiktok
- zeta suite
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Stone Game VI | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | Count Odd Numbers in an Interval Range | Easy | Solution |
| 2 | Merge Two Sorted Lists | Easy | Solution |
| 2 | Palindrome Number | Easy | Java, C++ |
| 1 | Find Subsequence of Length K With the Largest Sum | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Minimum ASCII Delete Sum for Two Strings | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 52 | Two Sum | Easy | Java, C++, Javascript |
| 19 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 16 | Roman to Integer | Easy | Solution |
| 13 | Reverse Integer | Easy | Solution, C++ |
| 12 | Maximum Subarray | Easy | Solution |
| 12 | Contains Duplicate | Easy | Solution |
| 12 | Longest Palindromic Substring | Medium | Solution |
| 11 | Merge Two Sorted Lists | Easy | Solution |
| 11 | Longest Common Prefix | Easy | Solution |
| 10 | Add Two Numbers | Medium | Solution |
| 9 | Container With Most Water | Medium | Solution |
| 9 | 3Sum | Medium | Solution, C++ |
| 8 | Valid Parentheses | Easy | Solution |
| 8 | Merge Intervals | Medium | Solution |
| 8 | First Missing Positive | Hard | Solution |
| 8 | Best Time to Buy and Sell Stock | Easy | Solution |
| 7 | Search Insert Position | Easy | Solution |
| 7 | Search in Rotated Sorted Array | Medium | Solution |
| 7 | Trapping Rain Water | Hard | Solution |
| 7 | Product of Array Except Self | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 10 | Insert Delete GetRandom O(1) | Medium | Solution |
| 6 | Design Hit Counter | Medium | Solution |
| 4 | Group Anagrams | Medium | Solution |
| 3 | Insert Delete GetRandom O(1) - Duplicates allowed | Hard | Solution |
| 3 | Valid Anagram | Easy | Solution |
| 2 | Optimal Account Balancing | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 14 | Palindrome Pairs | Hard | Solution |
| 14 | Alien Dictionary | nan | Solution |
| 9 | Flatten 2D Vector | Medium | Solution |
| 7 | Smallest Common Region | Medium | Solution |
| 6 | Pour Water | Medium | Solution |
| 6 | Minimum Window Substring | Hard | Solution |
| 5 | Combination Sum | Medium | Solution |
| 4 | Flatten Nested List Iterator | Medium | Solution |
| 3 | Design Circular Queue | Medium | Solution |
| 3 | Fraction to Recurring Decimal | Medium | Solution |
| 2 | Find the Smallest Divisor Given a Threshold | nan | Solution |
| 2 | Tag Validator | Hard | Solution |
| 2 | Intersection of Two Linked Lists | Easy | Solution |
| 1 | Pyramid Transition Matrix | Medium | Solution |
| 1 | Mini Parser | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | N-Repeated Element in Size 2N Array | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Increasing Decreasing String | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | H-Index | Medium | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Group Anagrams | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Path Sum IV | Medium | Solution |
| 1 | Split Concatenated Strings | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Number Of Rectangles That Can Form The Largest Square | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 117 | Two Sum | Easy | Java, C++, Javascript |
| 117 | LRU Cache | Hard | Solution |
| 103 | Number of Islands | Medium | Solution |
| 87 | Merge Intervals | Medium | Solution |
| 68 | Search Suggestions System | Medium | Solution |
| 56 | Best Time to Buy and Sell Stock | Easy | Solution |
| 51 | Group Anagrams | Medium | Solution |
| 50 | Analyze User Website Visit Pattern | Medium | Solution |
| 49 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 49 | K Closest Points to Origin | Easy | Solution |
| 48 | Meeting Rooms II | Medium | Solution |
| 47 | Merge k Sorted Lists | Hard | Solution |
| 45 | Trapping Rain Water | Hard | Solution |
| 44 | 3Sum | Medium | Solution, C++ |
| 43 | Valid Parentheses | Easy | Solution |
| 41 | Word Ladder | Hard | Solution |
| 40 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 36 | Add Two Numbers | Medium | Solution |
| 36 | Word Search | Medium | Solution |
| 35 | Maximum Subarray | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Reorder Routes to Make All Paths Lead to the City Zero | Medium | Solution |
| 3 | Valid Palindrome | Easy | Solution |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | Reducing Dishes | Hard | Solution |
| 2 | 3Sum | Medium | Solution, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 40 | Two Sum | Easy | Java, C++, Javascript |
| 20 | LRU Cache | Hard | Solution |
| 19 | Add Two Numbers | Medium | Solution |
| 18 | Merge Intervals | Medium | Solution |
| 17 | Maximum Subarray | Easy | Solution |
| 16 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 15 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 14 | Longest Common Prefix | Easy | Solution |
| 13 | Roman to Integer | Easy | Solution |
| 11 | Spiral Matrix | Medium | Solution |
| 11 | Group Anagrams | Medium | Solution |
| 11 | Number of Islands | Medium | Solution |
| 10 | Word Break | Medium | Solution |
| 10 | Product of Array Except Self | Medium | Solution |
| 10 | 3Sum | Medium | Solution, C++ |
| 9 | Generate Parentheses | Medium | Solution |
| 8 | Rotate Image | Medium | Solution |
| 8 | Move Zeroes | Easy | Solution |
| 8 | Best Time to Buy and Sell Stock | Easy | Solution |
| 8 | Merge k Sorted Lists | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Maximum Length of Subarray With Positive Product | Medium | Solution |
| 2 | Broken Calculator | Medium | Solution |
| 2 | Minimum Size Subarray Sum | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Valid Parentheses | Easy | Solution |
| 2 | Compare Version Numbers | Easy | Solution |
| 2 | Restore IP Addresses | Medium | Solution |
| 1 | Construct String With Repeat Limit | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 13 | Product of Array Except Self | Medium | Solution |
| 5 | K Closest Points to Origin | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Degree of an Array | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 18 | Rank Teams by Votes | Medium | Solution |
| 10 | Logger Rate Limiter | Easy | Solution |
| 4 | Lemonade Change | Easy | Solution |
| 3 | Design Snake Game | Medium | Solution |
| 2 | Greatest Common Divisor of Strings | Easy | Solution |
| 2 | Single Number | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Out of Boundary Paths | Hard | Solution |
| 1 | Zuma Game | Hard | Solution |
| 1 | Arithmetic Slices II - Subsequence | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Valid Parentheses | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 6 | Group Anagrams | Medium | Solution |
| 2 | Evaluate Division | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 64 | Design Underground System | Medium | Solution |
| 33 | Number of Islands | Medium | Solution |
| 33 | Decode String | Medium | Solution |
| 28 | Flatten a Multilevel Doubly Linked List | Medium | Solution |
| 26 | Remove All Adjacent Duplicates in String II | Medium | Solution |
| 23 | Insert Delete GetRandom O(1) | Medium | Solution |
| 23 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 20 | Merge Intervals | Medium | Solution |
| 20 | Meeting Rooms II | Medium | Solution |
| 20 | Design an Ordered Stream | Easy | Solution |
| 19 | LRU Cache | Hard | Solution |
| 16 | Two Sum | Easy | Java, C++, Javascript |
| 16 | Add Two Numbers | Medium | Solution |
| 15 | Trapping Rain Water | Hard | Solution |
| 14 | Validate Binary Search Tree | Medium | Solution |
| 14 | Two City Scheduling | Easy | Solution |
| 14 | Valid Parentheses | Easy | Solution |
| 14 | Word Search | Medium | Solution |
| 13 | First Unique Character in a String | Easy | Solution |
| 12 | Best Time to Buy and Sell Stock | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Check if All Characters Have Equal Number of Occurrences | Easy | Solution |
| 3 | Reverse Words in a String III | Easy | Solution |
| 3 | Word Pattern | Easy | Solution |
| 2 | Subarray Sum Equals K | Medium | Solution |
| 2 | Word Pattern II | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Least Number of Unique Integers after K Removals | Medium | Solution |
| 3 | Backspace String Compare | Easy | Solution |
| 3 | Additive Number | Medium | Solution |
| 2 | Integer to English Words | Hard | Solution |
| 2 | Sliding Window Maximum | Hard | Solution |
| 2 | Valid Parentheses | Easy | Solution |
| 1 | Two Out of Three | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 12 | Number of 1 Bits | Easy | Solution |
| 4 | Word Ladder II | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Merge k Sorted Lists | Hard | Solution |
| 6 | Number of Islands | Medium | Solution |
| 6 | Search in Rotated Sorted Array | Medium | Solution |
| 6 | Binary Tree Maximum Path Sum | Hard | Solution |
| 5 | LRU Cache | Hard | Solution |
| 4 | The Maze | Medium | Solution |
| 4 | Basic Calculator II | Medium | Solution |
| 4 | Sliding Window Maximum | Hard | Solution |
| 4 | The Number of Weak Characters in the Game | Medium | Solution |
| 3 | Best Time to Buy and Sell Stock II | Easy | Solution |
| 3 | Course Schedule II | Medium | Solution |
| 3 | Longest Valid Parentheses | Hard | Solution |
| 3 | Combination Sum | Medium | Solution |
| 3 | N-Queens | Hard | Solution |
| 3 | Maximum Subarray | Easy | Solution |
| 3 | Best Time to Buy and Sell Stock | Easy | Solution |
| 3 | Sort List | Medium | Solution |
| 3 | Closest Dessert Cost | Medium | Solution |
| 3 | 3Sum | Medium | Solution, C++ |
| 3 | Basic Calculator | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Pairs of Songs With Total Durations Divisible by 60 | Easy | Solution |
| 3 | Daily Temperatures | Medium | Solution |
| 3 | Generate Parentheses | Medium | Solution |
| 2 | Sort Array by Increasing Frequency | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Divide a String Into Groups of Size k | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 18 | License Key Formatting | Medium | Solution |
| 14 | Count Primes | Easy | Solution |
| 13 | Reverse Nodes in k-Group | Hard | Solution |
| 4 | Best Time to Buy and Sell Stock | Easy | Solution |
| 3 | Candy Crush | Medium | Solution |
| 3 | Integer to Roman | Medium | Solution |
| 2 | Rotating the Box | Medium | Solution |
| 2 | Restore the Array From Adjacent Pairs | Medium | Solution |
| 2 | Add Two Numbers | Medium | Solution |
| 1 | Four Divisors | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Maximum Erasure Value | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 16 | Word Search II | Hard | Solution |
| 16 | Rotate Image | Medium | Solution |
| 11 | Maximum Subarray | Easy | Solution |
| 11 | Expressive Words | Medium | Solution |
| 9 | Decode Ways | Medium | Solution |
| 8 | Validate IP Address | Medium | Solution |
| 8 | Decode String | Medium | Solution |
| 6 | House Robber | Easy | Solution |
| 6 | Maximum Difference Between Increasing Elements | Easy | Java |
| 5 | Valid Parentheses | Easy | Solution |
| 4 | Number of 1 Bits | Easy | Solution |
| 3 | Top K Frequent Elements | Medium | Solution |
| 3 | Beautiful Arrangement | Medium | Solution |
| 3 | Unique Paths II | Medium | Solution |
| 2 | Coin Change 2 | Medium | Solution |
| 2 | First Bad Version | Easy | Solution |
| 2 | Maximum Population Year | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Find Pivot Index | Easy | Solution |
| 2 | Merge Intervals | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Pairs of Songs With Total Durations Divisible by 60 | Easy | Solution |
| 5 | Range Addition | Medium | Solution |
| 4 | Sliding Window Maximum | Hard | Solution |
| 2 | Transpose Matrix | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock IV | Hard | Solution |
| 2 | Trapping Rain Water | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find All Groups of Farmland | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Largest BST Subtree | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Vowel Substrings of a String | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Rank Teams by Votes | Medium | Solution |
| 2 | Wildcard Matching | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 9 | Unique Paths II | Medium | Solution |
| 5 | Valid Sudoku | Medium | Solution, Javascript |
| 3 | Synonymous Sentences | Medium | Solution |
| 3 | The Skyline Problem | Hard | Solution |
| 2 | Product of the Last K Numbers | Medium | Solution |
| 2 | Car Pooling | Medium | Solution |
| 2 | Decode String | Medium | Solution |
| 2 | Palindrome Permutation II | Medium | Solution |
| 2 | Number of Islands | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Freedom Trail | Hard | Solution |
| 2 | Sliding Window Maximum | Hard | Solution |
| 1 | Number of Substrings Containing All Three Characters | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Three Consecutive Odds | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Reorder Routes to Make All Paths Lead to the City Zero | Medium | Solution |
| 1 | Counting Elements | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 9 | Design Hit Counter | Medium | Solution |
| 2 | Sparse Matrix Multiplication | Medium | Solution |
| 2 | First Missing Positive | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Valid Parentheses | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Two Sum | Easy | Java, C++, Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | The Time When the Network Becomes Idle | Medium | Java |
| 1 | Minimum Operations to Make the Array Increasing | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find the Winner of an Array Game | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Number of Islands | Medium | Solution |
| 3 | Maximum Subarray | Easy | Solution |
| 2 | Implement Trie II (Prefix Tree) | Medium | Solution |
| 2 | Rectangle Overlap | Easy | Solution |
| 2 | Minesweeper | Medium | Solution |
| 2 | LRU Cache | Hard | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 18 | Binary Tree Maximum Path Sum | Hard | Solution |
| 13 | Buddy Strings | Easy | Solution |
| 11 | Walls and Gates | Medium | Solution |
| 7 | Minimum Number of Steps to Make Two Strings Anagram | Easy | Solution |
| 7 | Asteroid Collision | Medium | Solution |
| 7 | Serialize and Deserialize Binary Tree | Hard | Solution |
| 6 | Basic Calculator | Hard | Solution |
| 5 | Shortest Distance from All Buildings | Hard | Solution |
| 5 | Longest Common Subsequence | Medium | Solution |
| 5 | Number of Islands | Medium | Solution |
| 4 | Integer to English Words | Hard | Solution |
| 4 | Sudoku Solver | Hard | Solution |
| 4 | Design In-Memory File System | Hard | Solution |
| 4 | Car Pooling | Medium | Solution |
| 3 | Path Sum III | Easy | Solution |
| 3 | Jump Game | Medium | Solution |
| 3 | Jump Game II | Hard | Solution |
| 3 | Find Nearest Point That Has the Same X or Y Coordinate | Easy | Solution |
| 2 | K-diff Pairs in an Array | Easy | Solution |
| 2 | Subarray Sum Equals K | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Set Intersection Size At Least Two | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 6 | Find Duplicate File in System | Medium | Solution |
| 5 | Game of Life | Medium | Solution |
| 2 | Max Area of Island | Medium | Solution |
| 2 | Design Phone Directory | Medium | Solution |
| 2 | Number of Islands | Medium | Solution |
| 1 | Seat Reservation Manager | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Maximize Sum Of Array After K Negations | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Maximum Number of Coins You Can Get | Medium | Solution |
| 2 | Max Sum of Rectangle No Larger Than K | Hard | Solution |
| 1 | Stone Game VII | Medium | Solution |
| 1 | Ways to Make a Fair Array | Medium | Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Minimum Number of People to Teach | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Letter Combinations of a Phone Number | Medium | Solution |
| 2 | Additive Number | Medium | Solution |
| 1 | Self Dividing Numbers | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 14 | Reformat Date | Easy | Solution |
| 14 | Making File Names Unique | Medium | Solution |
| 8 | String Compression | Easy | Solution |
| 7 | Two Sum | Easy | Java, C++, Javascript |
| 7 | Climbing Stairs | Easy | Solution |
| 6 | The kth Factor of n | Medium | Solution |
| 6 | Valid Parentheses | Easy | Solution |
| 5 | Degree of an Array | Easy | Solution |
| 5 | Best Time to Buy and Sell Stock | Easy | Solution |
| 4 | Best Meeting Point | Hard | Solution |
| 4 | Least Number of Unique Integers after K Removals | Medium | Solution |
| 3 | Integer to English Words | Hard | Solution |
| 3 | Maximum Difference Between Increasing Elements | Easy | Java |
| 2 | Move Zeroes | Easy | Solution |
| 2 | Number of Different Integers in a String | Medium | Solution |
| 2 | Palindromic Substrings | Medium | Solution |
| 2 | Find Pivot Index | Easy | Solution |
| 2 | Search in Rotated Sorted Array | Medium | Solution |
| 2 | Subarray Sum Equals K | Medium | Solution |
| 1 | Rearrange Words in a Sentence | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find Three Consecutive Integers That Sum to a Given Number | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 282 | Minimum Remove to Make Valid Parentheses | Medium | Solution |
| 252 | Valid Palindrome II | Easy | Solution |
| 188 | Binary Tree Vertical Order Traversal | Medium | Solution |
| 180 | Lowest Common Ancestor of a Binary Tree | Medium | Solution |
| 162 | Pow(x, n) | Medium | Solution |
| 156 | Lowest Common Ancestor of a Binary Tree III | Medium | Solution |
| 149 | Range Sum of BST | Medium | Solution |
| 141 | Subarray Sum Equals K | Medium | Solution |
| 140 | Random Pick with Weight | Medium | Solution |
| 140 | Kth Largest Element in an Array | Medium | Solution |
| 127 | K Closest Points to Origin | Easy | Solution |
| 121 | Dot Product of Two Sparse Vectors | Easy | Solution |
| 118 | Basic Calculator II | Medium | Solution |
| 114 | Valid Word Abbreviation | Easy | Solution |
| 112 | Simplify Path | Medium | Solution |
| 110 | Merge Intervals | Medium | Solution |
| 108 | Binary Tree Right Side View | Medium | Solution |
| 100 | Minimum Add to Make Parentheses Valid | Medium | Solution |
| 100 | Nested List Weight Sum | Easy | Solution |
| 97 | Top K Frequent Elements | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Maximal Square | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 7 | Number of Students Unable to Eat Lunch | Easy | Solution |
| 4 | Car Pooling | Medium | Solution |
| 3 | Maximum Number of Coins You Can Get | Medium | Solution |
| 3 | Jump Game | Medium | Solution |
| 2 | Shortest Subarray to be Removed to Make Array Sorted | Medium | Solution |
| 2 | Maximum Length of Pair Chain | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Add One Row to Tree | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Battleships in a Board | Medium | Solution |
| 2 | LRU Cache | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 38 | Trapping Rain Water | Hard | Solution |
| 20 | Height Checker | Easy | Solution |
| 18 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 12 | High Five | Easy | Solution |
| 11 | Best Time to Buy and Sell Stock | Easy | Solution |
| 11 | Delete and Earn | Medium | Solution |
| 9 | Find Pivot Index | Easy | Solution |
| 7 | Two Sum | Easy | Java, C++, Javascript |
| 7 | Count Number of Teams | Medium | Solution |
| 6 | String Compression | Easy | Solution |
| 6 | LRU Cache | Hard | Solution |
| 5 | Longest Palindromic Substring | Medium | Solution |
| 5 | Fraction Addition and Subtraction | Medium | Solution |
| 4 | Elimination Game | Medium | Solution |
| 4 | Find the Winner of the Circular Game | Medium | Solution |
| 4 | 3Sum | Medium | Solution, C++ |
| 4 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 4 | Minimum Moves to Equal Array Elements | Easy | Solution |
| 4 | First Unique Character in a String | Easy | Solution |
| 3 | Minimum Path Sum | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 75 | Find Leaves of Binary Tree | Medium | Solution |
| 73 | Evaluate Reverse Polish Notation | Medium | Solution |
| 44 | Two Sum | Easy | Java, C++, Javascript |
| 36 | Snapshot Array | Easy | Javascript |
| 30 | Stock Price Fluctuation | Medium | Java |
| 30 | Minimum Time Difference | Medium | Solution |
| 28 | Merge Intervals | Medium | Solution |
| 27 | Random Pick with Weight | Medium | Solution |
| 24 | Text Justification | Hard | Solution |
| 22 | Meeting Rooms II | Medium | Solution |
| 22 | Happy Number | Easy | Solution |
| 22 | Logger Rate Limiter | Easy | Solution |
| 21 | Number of Islands | Medium | Solution |
| 19 | First Bad Version | Easy | Solution |
| 19 | Decode String | Medium | Solution |
| 17 | Maximum Points You Can Obtain from Cards | Medium | Solution |
| 15 | Unique Paths | Medium | Solution |
| 15 | Number of Matching Subsequences | Medium | Solution |
| 15 | Subarray Sum Equals K | Medium | Solution |
| 14 | Student Attendance Record II | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Bulb Switcher III | Medium | Solution |
| 3 | Sort Colors | Medium | Solution |
| 2 | Reorder Routes to Make All Paths Lead to the City Zero | Medium | Solution |
| 2 | Number of Steps to Reduce a Number to Zero | Easy | Solution |
| 2 | Brick Wall | Medium | Solution |
| 2 | First Missing Positive | Hard | Solution |
| 1 | Minimum Number of Buckets Required to Collect Rainwater from Houses | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Short Encoding of Words | Medium | Solution |
| 2 | Sliding Window Median | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 7 | Equal Sum Arrays With Minimum Number of Operations | Medium | Solution |
| 3 | 24 Game | Hard | Solution |
| 3 | Find Peak Element | Binary Search | Solution |
| 1 | Detect Pattern of Length M Repeated K or More Times | Easy | Solution |
| 1 | Maximum 69 Number | Easy | Solution |
| 1 | Convert Integer to the Sum of Two No-Zero Integers | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Minimum Distance to the Target Element | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Asteroid Collision | Medium | Solution |
| 2 | Keys and Rooms | Easy | Solution |
| 2 | Find K Pairs with Smallest Sums | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Add Two Numbers | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | K-th Smallest in Lexicographical Order | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Gas Station | Medium | Solution |
| 8 | Merge Intervals | Medium | Solution |
| 6 | Most Visited Sector in a Circular Track | Easy | Solution |
| 6 | Backspace String Compare | Easy | Solution |
| 4 | Water Bottles | Easy | Solution |
| 3 | Degree of an Array | Easy | Solution |
| 3 | Maximal Square | Medium | Solution |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | Move Zeroes | Easy | Solution |
| 2 | Group Anagrams | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Score After Flipping Matrix | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Artifacts That Can Be Extracted | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Design Snake Game | Medium | Solution |
| 1 | Find the Derangement of An Array | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 25 | Subdomain Visit Count | Easy | Solution |
| 9 | Word Search | Medium | Solution |
| 8 | Maximum Length of Repeated Subarray | Medium | Solution |
| 6 | Find Words That Can Be Formed by Characters | Easy | Solution |
| 4 | Alert Using Same Key-Card Three or More Times in a One Hour Period | Medium | Solution |
| 3 | Text Justification | Hard | Solution |
| 3 | Merge k Sorted Lists | Hard | Solution |
| 2 | Merge Sorted Array | Easy | Solution |
| 1 | Sum of Even Numbers After Queries | Easy | Solution |
| 1 | Binary Tree Tilt | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find the Minimum and Maximum Number of Nodes Between Critical Points | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Maximum Product Subarray | Medium | Solution |
| 2 | Sort Integers by The Number of 1 Bits | Easy | Solution |
| 2 | Score of Parentheses | Medium | Solution |
| 2 | Maximum Subarray | Easy | Solution |
| 2 | 4 Sum | Medium | Solution |
| 2 | 3Sum | Medium | Solution, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Valid Parentheses | Easy | Solution |
| 3 | Trapping Rain Water | Hard | Solution |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | Reverse String | Easy | Solution |
| 2 | Sort Colors | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | LRU Cache | Hard | Solution |
| 6 | Unique Email Addresses | Easy | Solution |
| 4 | Sudoku Solver | Hard | Solution |
| 3 | Boats to Save People | Medium | Solution |
| 2 | Delete Nodes And Return Forest | Medium | Solution |
| 2 | Subdomain Visit Count | Easy | Solution |
| 2 | Decode String | Medium | Solution |
| 2 | Palindrome Linked List | Easy | Solution |
| 2 | Reverse Linked List | Easy | Solution |
| 2 | Merge Intervals | Medium | Solution |
| 2 | Trapping Rain Water | Hard | Solution |
| 2 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 2 | Two Sum | Easy | Java, C++, Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 69 | Reconstruct Original Digits from English | Medium | Solution |
| 8 | Group Anagrams | Medium | Solution |
| 5 | Maximum Subarray | Easy | Solution |
| 3 | Even Odd Tree | Medium | Solution |
| 3 | Best Time to Buy and Sell Stock | Easy | Solution |
| 3 | Add Two Numbers | Medium | Solution |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | Maximum Units on a Truck | Easy | Solution |
| 2 | Minimum Value to Get Positive Step by Step Sum | Easy | Solution |
| 2 | Maximum Number of Events That Can Be Attended | Medium | Solution |
| 2 | Minimum Absolute Difference | Easy | Solution |
| 2 | Intersection of Two Arrays | Easy | Solution |
| 2 | Counting Bits | Medium | Solution |
| 2 | Paint Fence | Easy | Solution |
| 2 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 1 | Determine Color of a Chessboard Square | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Common Words With One Occurrence | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Minimum Moves to Convert String | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 40 | Subdomain Visit Count | Easy | Solution |
| 17 | Word Search | Medium | Solution |
| 16 | Alert Using Same Key-Card Three or More Times in a One Hour Period | Medium | Solution |
| 16 | Maximum Length of Repeated Subarray | Medium | Solution |
| 12 | Find Words That Can Be Formed by Characters | Easy | Solution |
| 10 | Text Justification | Hard | Solution |
| 5 | Word Search II | Hard | Solution |
| 4 | Check if Every Row and Column Contains All Numbers | Easy | Java |
| 4 | Course Schedule II | Medium | Solution |
| 4 | Number of Islands | Medium | Solution |
| 3 | Lowest Common Ancestor of a Binary Tree | Medium | Solution |
| 3 | Valid Sudoku | Medium | Solution, Javascript |
| 2 | Longest Common Subsequence | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Generate Random Point in a Circle | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 71 | Shortest Word Distance II | Medium | Solution |
| 48 | Nested List Weight Sum II | Medium | Solution |
| 43 | Maximum Subarray | Easy | Solution |
| 34 | Nested List Weight Sum | Easy | Solution |
| 33 | Valid Parentheses | Easy | Solution |
| 33 | Max Stack | Hard | Solution |
| 29 | Maximum Product Subarray | Medium | Solution |
| 26 | Closest Binary Search Tree Value II | Hard | Solution |
| 21 | Can Place Flowers | Easy | Solution |
| 18 | Serialize and Deserialize Binary Tree | Hard | Solution |
| 18 | Text Justification | Hard | Solution |
| 18 | Lowest Common Ancestor of a Binary Search Tree | Easy | Solution |
| 17 | Search in Rotated Sorted Array | Medium | Solution |
| 17 | All O`one Data Structure | Hard | Solution |
| 16 | Number of Islands | Medium | Solution |
| 15 | Insert Delete GetRandom O(1) | Medium | Solution |
| 14 | Kth Largest Element in an Array | Medium | Solution |
| 13 | Find Leaves of Binary Tree | Medium | Solution |
| 11 | Shortest Word Distance | Easy | Solution |
| 11 | Second Minimum Node In a Binary Tree | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Minesweeper | Medium | Solution |
| 3 | Spiral Matrix | Medium | Solution |
| 1 | Longest Harmonious Subsequence | Easy | Solution |
| 1 | Distribute Candies | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 9 | Minimum Window Substring | Hard | Solution |
| 8 | Read N Characters Given Read4 II - Call multiple times | Hard | Solution |
| 7 | Time Based Key-Value Store | Medium | Solution |
| 7 | Decode Ways | Medium | Solution |
| 4 | Asteroid Collision | Medium | Solution |
| 4 | Water and Jug Problem | Medium | Solution |
| 4 | Range Sum Query 2D - Immutable | Medium | Solution |
| 4 | Word Ladder | Hard | Solution |
| 2 | Max Stack | Hard | Solution |
| 2 | Read N Characters Given Read4 | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Unique Substrings in Wraparound String | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Remove All Occurrences of a Substring | Medium | Solution |
| 2 | Remove K Digits | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Coin Change | Medium | Solution |
| 5 | Fraction to Recurring Decimal | Medium | Solution |
| 3 | Degree of an Array | Easy | Solution |
| 3 | Minimum Moves to Equal Array Elements | Easy | Solution |
| 3 | Distinct Subsequences | Hard | Solution |
| 2 | Keyboard Row | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Crawler Log Folder | Easy | Solution |
| 1 | Max Difference You Can Get From Changing an Integer | Medium | Solution |
| 1 | Minimum Subsequence in Non-Increasing Order | Easy | Solution |
| 1 | Count Largest Group | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 52 | LRU Cache | Hard | Solution |
| 45 | Sign of the Product of an Array | Easy | Solution |
| 42 | Number of Islands | Medium | Solution |
| 39 | Two Sum | Easy | Java, C++, Javascript |
| 34 | Reverse Words in a String | Medium | Solution |
| 29 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 29 | Group Anagrams | Medium | Solution |
| 26 | Spiral Matrix | Medium | Solution |
| 24 | Search in Rotated Sorted Array | Medium | Solution |
| 22 | Valid Parentheses | Easy | Solution |
| 22 | Find N Unique Integers Sum up to Zero | Easy | Solution |
| 20 | 3Sum | Medium | Solution, C++ |
| 20 | Letter Combinations of a Phone Number | Medium | Solution |
| 20 | Serialize and Deserialize Binary Tree | Hard | Solution |
| 18 | Longest Palindromic Substring | Medium | Solution |
| 17 | Add Two Numbers | Medium | Solution |
| 17 | Merge k Sorted Lists | Hard | Solution |
| 17 | Cinema Seat Allocation | Medium | Solution |
| 16 | First Missing Positive | Hard | Solution |
| 16 | String to Integer (atoi) | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Maximum Frequency Stack | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Integers With Even Digit Sum | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Redistribute Characters to Make All Strings Equal | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Longest Valid Parentheses | Hard | Solution |
| 3 | 3Sum | Medium | Solution, C++ |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | LRU Cache | Hard | Solution |
| 2 | Merge Intervals | Medium | Solution |
| 2 | Search in Rotated Sorted Array | Medium | Solution |
| 1 | Best Team With No Conflicts | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Trapping Rain Water | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Rotating the Box | Medium | Solution |
| 3 | Logger Rate Limiter | Easy | Solution |
| 2 | Reconstruct Itinerary | Medium | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Valid Parentheses | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Average Salary Excluding the Minimum and Maximum Salary | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Subrectangle Queries | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Compare Version Numbers | Easy | Solution |
| 2 | Sudoku Solver | Hard | Solution |
| 1 | Check If Word Is Valid After Substitutions | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Last Stone Weight | Easy | Solution |
| 4 | Serialize and Deserialize Binary Tree | Hard | Solution |
| 4 | Regular Expression Matching | Hard | Java, Javascript |
| 3 | Design Circular Queue | Medium | Solution |
| 3 | Number of Islands | Medium | Solution |
| 3 | Valid Sudoku | Medium | Solution, Javascript |
| 3 | Sort Colors | Medium | Solution |
| 3 | LRU Cache | Hard | Solution |
| 3 | Intersection of Two Linked Lists | Easy | Solution |
| 3 | Best Time to Buy and Sell Stock IV | Hard | Solution |
| 3 | Lonely Pixel I | Medium | Solution |
| 2 | Degree of an Array | Easy | Solution |
| 2 | Add and Search Word - Data structure design | Medium | Solution |
| 2 | Subarray Sum Equals K | Medium | Solution |
| 2 | Missing Number | nan | Solution |
| 2 | K Empty Slots | Hard | Solution |
| 2 | Search a 2D Matrix | Medium | Solution |
| 2 | Merge Intervals | Medium | Solution |
| 2 | Single Element in a Sorted Array | Medium | Solution |
| 2 | Search in Rotated Sorted Array | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Reducing Dishes | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 10 | Game of Life | Medium | Solution |
| 3 | Design Excel Sum Formula | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Reverse Prefix of Word | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 13 | LRU Cache | Hard | Solution |
| 13 | Meeting Rooms II | Medium | Solution |
| 9 | Number of Islands | Medium | Solution |
| 7 | Subarray Sum Equals K | Medium | Solution |
| 7 | Longest Palindromic Substring | Medium | Solution |
| 7 | Top K Frequent Elements | Medium | Solution |
| 6 | Decode String | Medium | Solution |
| 6 | Two Sum | Easy | Java, C++, Javascript |
| 6 | Valid Parentheses | Easy | Solution |
| 5 | Search in Rotated Sorted Array | Medium | Solution |
| 5 | First Unique Character in a String | Easy | Solution |
| 4 | Delete Node in a BST | Medium | Solution |
| 4 | Binary Tree Level Order Traversal | Medium | Solution |
| 4 | Add Two Numbers | Medium | Solution |
| 4 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 4 | Merge Two Sorted Lists | Easy | Solution |
| 4 | Add Strings | Easy | Solution |
| 4 | Best Time to Buy and Sell Stock | Easy | Solution |
| 4 | Product of Array Except Self | Medium | Solution |
| 4 | Merge Intervals | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | UTF-8 Validation | Medium | Solution |
| 1 | Check If It Is a Straight Line | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Distribute Candies to People | Easy | Solution |
| 2 | Reverse Words in a String III | Easy | Solution |
| 2 | Maximum Subarray | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Happy Number | Easy | Solution |
| 3 | Number of Islands | Medium | Solution |
| 3 | Trapping Rain Water | Hard | Solution |
| 3 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 2 | Reverse Substrings Between Each Pair of Parentheses | Medium | Solution |
| 2 | Squares of a Sorted Array | Easy | Solution |
| 2 | LRU Cache | Hard | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | ZigZag Conversion | Easy | Solution |
| 2 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Distribute Coins in Binary Tree | Medium | Solution |
| 1 | Simple Bank System | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Parallel Courses III | Hard | Java |
| 3 | Find the Celebrity | Medium | Solution |
| 2 | Accounts Merge | Medium | Solution |
| 2 | Number of Connected Components in an Undirected Graph | Medium | Solution |
| 2 | Word Pattern II | Hard | Solution |
| 2 | Alien Dictionary | nan | Solution |
| 2 | Clone Graph | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Non-negative Integers without Consecutive Ones | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Print Words Vertically | Medium | Solution |
| 1 | Determine if Two Strings Are Close | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Maximum Repeating Substring | Easy | Solution |
| 2 | Valid Square | Medium | Java, Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Reverse Bits | Easy | Solution |
| 2 | Middle of the Linked List | Easy | Solution |
| 2 | Find the Duplicate Number | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 7 | Word Break | Medium | Solution |
| 6 | Word Ladder | Hard | Solution |
| 5 | 3Sum | Medium | Solution, C++ |
| 4 | Max Area of Island | Medium | Solution |
| 4 | Binary Tree Right Side View | Medium | Solution |
| 4 | Unique Paths II | Medium | Solution |
| 4 | Trapping Rain Water | Hard | Solution |
| 3 | First Unique Character in a String | Easy | Solution |
| 3 | Number of Islands | Medium | Solution |
| 2 | Sort Integers by The Power Value | Medium | Solution |
| 2 | Fixed Point | Easy | Solution |
| 2 | Summary Ranges | Medium | Solution |
| 2 | Longest Consecutive Sequence | Hard | Solution |
| 2 | Validate Binary Search Tree | Medium | Solution |
| 2 | Jump Game | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Construct Target Array With Multiple Sums | Hard | Solution |
| 3 | Subarray Sum Equals K | Medium | Solution |
| 3 | Longest Common Prefix | Easy | Solution |
| 2 | Sliding Window Maximum | Hard | Solution |
| 1 | Range Frequency Queries | Medium | Java |
| 1 | Maximum Number of Words You Can Type | Easy | Solution |
| 1 | Substrings of Size Three with Distinct Characters | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Sum of Floored Pairs | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Subsets | Medium | Solution |
| 3 | Text Justification | Hard | Solution |
| 3 | Combination Sum II | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | String Compression | Easy | Solution |
| 3 | String to Integer (atoi) | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Teemo Attacking | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Alert Using Same Key-Card Three or More Times in a One Hour Period | Medium | Solution |
| 7 | Course Schedule II | Medium | Solution |
| 3 | Insert Intervals | Hard | Solution |
| 1 | Count Good Meals | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Design Browser History | Medium | Solution |
| 5 | Course Schedule II | Medium | Solution |
| 4 | Minimum Falling Path Sum II | Hard | Solution |
| 2 | Number of Matching Subsequences | Medium | Solution |
| 2 | Find Peak Element | Binary Search | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Snapshot Array | Easy | Javascript |
| 4 | Kth Smallest Number in Multiplication Table | Hard | Solution |
| 4 | Trapping Rain Water | Hard | Solution |
| 2 | Task Scheduler | Medium | Solution |
| 2 | Majority Element | Easy | Solution |
| 2 | Read N Characters Given Read4 | Easy | Solution |
| 2 | Edit Distance | Hard | Solution |
| 2 | Rotate Image | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find Kth Bit in Nth Binary String | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 9 | Monotone Increasing Digits | Medium | Solution |
| 4 | Number of Islands | Medium | Solution |
| 3 | Longest Common Prefix | Easy | Solution |
| 2 | Prison Cells After N Days | Medium | Solution |
| 2 | Count Primes | Easy | Solution |
| 2 | Add Two Numbers | Medium | Solution |
| 1 | Maximum Students Taking Exam | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 19 | Merge Intervals | Medium | Solution |
| 10 | LRU Cache | Hard | Solution |
| 7 | Maximum Product of Three Numbers | Easy | Solution |
| 6 | Largest Number | Medium | Solution |
| 6 | Number of Islands | Medium | Solution |
| 6 | Sliding Window Maximum | Hard | Solution |
| 6 | Zuma Game | Hard | Solution |
| 5 | Boats to Save People | Medium | Solution |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 3 | Min Stack | Easy | Solution |
| 3 | Course Schedule II | Medium | Solution |
| 3 | Maximal Square | Medium | Solution |
| 3 | Construct the Lexicographically Largest Valid Sequence | Medium | Solution |
| 3 | Integer to English Words | Hard | Solution |
| 3 | Sort Colors | Medium | Solution |
| 3 | Design In-Memory File System | Hard | Solution |
| 3 | Design HashMap | Easy | Solution |
| 3 | Maximum Subarray | Easy | Solution |
| 3 | Group Anagrams | Medium | Solution |
| 3 | Minimum Absolute Difference | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Maximum Subarray | Easy | Solution |
| 2 | Range Sum Query 2D - Immutable | Medium | Solution |
| 2 | Reorder List | Medium | Solution |
| 2 | Reverse Integer | Easy | Solution, C++ |
| 2 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 2 | Two Sum | Easy | Java, C++, Javascript |
| 1 | Maximum Product of Two Elements in an Array | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Trapping Rain Water | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 3 | Number of Islands | Medium | Solution |
| 3 | Binary Tree Level Order Traversal | Medium | Solution |
| 3 | Group Anagrams | Medium | Solution |
| 3 | Search in Rotated Sorted Array | Medium | Solution |
| 2 | Pairs of Songs With Total Durations Divisible by 60 | Easy | Solution |
| 2 | Rectangle Overlap | Easy | Solution |
| 2 | Subarray Sum Equals K | Medium | Solution |
| 2 | Palindrome Linked List | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Maximum Subarray | Easy | Solution |
| 2 | Trapping Rain Water | Hard | Solution |
| 2 | Valid Parentheses | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Maximum Subarray | Easy | Solution |
| 4 | Merge Sorted Array | Easy | Solution |
| 4 | Merge Intervals | Medium | Solution |
| 3 | Palindrome Pairs | Hard | Solution |
| 3 | Number of Islands | Medium | Solution |
| 3 | Construct Binary Tree from Inorder and Postorder Traversal | Medium | Solution |
| 3 | Merge Two Sorted Lists | Easy | Solution |
| 2 | LRU Cache | Hard | Solution |
| 2 | Merge k Sorted Lists | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 7 | Word Search | Medium | Solution |
| 5 | Decode String | Medium | Solution |
| 5 | Sparse Matrix Multiplication | Medium | Solution |
| 5 | Evaluate Division | Medium | Solution |
| 5 | Word Search II | Hard | Solution |
| 5 | Merge Intervals | Medium | Solution |
| 4 | Find Peak Element | Binary Search | Solution |
| 4 | Implement Trie | Medium | Solution |
| 4 | Word Ladder | Hard | Solution |
| 3 | Add Binary | Easy | Solution |
| 3 | Binary Tree Maximum Path Sum | Hard | Solution |
| 3 | Basic Calculator II | Medium | Solution |
| 3 | LRU Cache | Hard | Solution |
| 3 | Word Break II | Hard | Solution |
| 3 | Word Ladder II | Hard | Solution |
| 3 | Shortest Path in Binary Matrix | Medium | Solution |
| 3 | Android Unlock Patterns | Medium | Solution |
| 3 | Subarray Sums Divisible by K | Medium | Solution |
| 3 | LFU Cache | Hard | Solution |
| 3 | The Maze | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Second Largest Digit in a String | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Reducing Dishes | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Search in Rotated Sorted Array | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 16 | Moving Average from Data Stream | Easy | Solution |
| 13 | Valid Parentheses | Easy | Solution |
| 10 | Ransom Note | Easy | Solution |
| 10 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 8 | Valid Anagram | Easy | Solution |
| 8 | Two Sum | Easy | Java, C++, Javascript |
| 6 | Analyze User Website Visit Pattern | Medium | Solution |
| 4 | Sliding Window Median | Hard | Solution |
| 4 | Linked List Cycle | Easy | Solution |
| 4 | Balanced Binary Tree | Easy | Solution |
| 4 | Maximum Depth of Binary Tree | Easy | Solution |
| 3 | Longest Consecutive Sequence | Hard | Solution |
| 2 | Lowest Common Ancestor of a Binary Tree III | Medium | Solution |
| 2 | Remove All Adjacent Duplicates in String II | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Max Points on a Line | Hard | Solution |
| 2 | Binary Tree Maximum Path Sum | Hard | Solution |
| 2 | Merge k Sorted Lists | Hard | Solution |
| 1 | Next Greater Numerically Balanced Number | Medium | Java |
| 1 | Maximum Subarray Sum After One Operation | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Design Snake Game | Medium | Solution |
| 3 | Text Justification | Hard | Solution |
| 2 | Rank Teams by Votes | Medium | Solution |
| 2 | Available Captures for Rook | Easy | Solution |
| 2 | Unique Morse Code Words | Easy | Solution |
| 2 | The Maze | Medium | Solution |
| 2 | Number of Islands | Medium | Solution |
| 2 | Minimum Path Sum | Medium | Solution |
| 1 | Squirrel Simulation | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Lowest Common Ancestor of a Binary Tree | Medium | Solution |
| 2 | Lowest Common Ancestor of a Binary Tree III | Medium | Solution |
| 2 | K Closest Points to Origin | Easy | Solution |
| 2 | Decode String | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Container With Most Water | Medium | Solution |
| 3 | Letter Combinations of a Phone Number | Medium | Solution |
| 2 | Rabbits in Forest | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Grid Game | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find Greatest Common Divisor of Array | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Minimum Factorization | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Largest Perimeter Triangle | Easy | Solution |
| 3 | Trapping Rain Water | Hard | Solution |
| 2 | Minimum Changes To Make Alternating Binary String | Easy | Solution |
| 2 | Find Winner on a Tic Tac Toe Game | Easy | Solution |
| 2 | Spiral Matrix III | Medium | Solution |
| 2 | Basic Calculator II | Medium | Solution |
| 2 | Jump Game II | Hard | Solution |
| 2 | Generate Parentheses | Medium | Solution |
| 2 | 3Sum | Medium | Solution, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Vowel Spellchecker | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Find Closest Number to Zero | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 3 | Reformat Phone Number | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Minimum ASCII Delete Sum for Two Strings | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Binary Tree Postorder Traversal | Easy | Solution |
| 2 | Binary Tree Maximum Path Sum | Hard | Solution |
| 2 | Merge k Sorted Lists | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 7 | LRU Cache | Hard | Solution |
| 5 | Course Schedule II | Medium | Solution |
| 3 | Subarray Sums Divisible by K | Medium | Solution |
| 3 | Sliding Window Maximum | Hard | Solution |
| 3 | Text Justification | Hard | Solution |
| 3 | Group Anagrams | Medium | Solution |
| 2 | Sort Array by Increasing Frequency | Easy | Solution |
| 2 | Knight Dialer | Medium | Solution |
| 2 | Binary Tree Maximum Path Sum | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 7 | Battleships in a Board | Medium | Solution |
| 2 | Number of Islands | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 23 | Word Search | Medium | Solution |
| 10 | Finding the Users Active Minutes | Medium | Solution |
| 7 | Design Hit Counter | Medium | Solution |
| 6 | Tweet Counts Per Frequency | Medium | Solution |
| 6 | Implement Trie | Medium | Solution |
| 5 | Insert Delete GetRandom O(1) | Medium | Solution |
| 5 | Word Search II | Hard | Solution |
| 5 | Design Log Storage System | Medium | Solution |
| 4 | Paint House | Medium | Solution |
| 4 | Reconstruct Itinerary | Medium | Solution |
| 3 | Minimum Moves to Equal Array Elements | Easy | Solution |
| 3 | Subsets | Medium | Solution |
| 3 | Flatten Nested List Iterator | Medium | Solution |
| 3 | Rearrange String k Distance Apart | Hard | Solution |
| 3 | Merge Intervals | Medium | Solution |
| 3 | Accounts Merge | Medium | Solution |
| 2 | Random Pick with Weight | Medium | Solution |
| 2 | Design Search Autocomplete System | Hard | Solution |
| 2 | Palindromic Substrings | Medium | Solution |
| 2 | Maximum Frequency Stack | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Maximum Product of Splitted Binary Tree | Medium | Solution |
| 4 | Multiply Strings | Medium | Solution |
| 2 | Top K Frequent Words | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 36 | Word Search II | Hard | Solution |
| 17 | Word Search | Medium | Solution |
| 17 | Top K Frequent Words | Medium | Solution |
| 14 | Evaluate Division | Medium | Solution |
| 14 | Merge Intervals | Medium | Solution |
| 14 | Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit | Medium | Solution |
| 13 | Random Pick with Weight | Medium | Solution |
| 12 | Dungeon Game | Hard | Solution |
| 11 | Two Sum | Easy | Java, C++, Javascript |
| 11 | Kth Smallest Element in a BST | Medium | Solution |
| 10 | Leftmost Column with at Least a One | Medium | Solution |
| 10 | Reconstruct Itinerary | Medium | Solution |
| 9 | Letter Combinations of a Phone Number | Medium | Solution |
| 8 | Product of Array Except Self | Medium | Solution |
| 8 | Optimal Account Balancing | Hard | Solution |
| 7 | Construct K Palindrome Strings | Medium | Solution |
| 7 | Number of Islands | Medium | Solution |
| 7 | Best Time to Buy and Sell Stock | Easy | Solution |
| 7 | Insert Delete GetRandom O(1) | Medium | Solution |
| 7 | Minesweeper | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Check If All 1's Are at Least Length K Places Away | Medium | Solution |
| 1 | Day of the Week | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 5 | Valid Parentheses | Easy | Solution |
| 5 | Merge Intervals | Medium | Solution |
| 4 | Maximum Subarray | Easy | Solution |
| 4 | Course Schedule II | Medium | Solution |
| 4 | Merge k Sorted Lists | Hard | Solution |
| 4 | Verify Preorder Sequence in Binary Search Tree | Medium | Solution |
| 4 | Rotting Oranges | Medium | Solution |
| 3 | 3Sum | Medium | Solution, C++ |
| 3 | Max Stack | Hard | Solution |
| 3 | Search in Rotated Sorted Array | Medium | Solution |
| 3 | Number of Islands | Medium | Solution |
| 3 | Sort Colors | Medium | Solution |
| 2 | Remove Duplicates from Sorted Array | Easy | Solution |
| 2 | Longest Valid Parentheses | Hard | Solution |
| 2 | Search Insert Position | Easy | Solution |
| 2 | Group Anagrams | Medium | Solution |
| 2 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 2 | Rearrange Words in a Sentence | Medium | Solution |
| 2 | Validate Binary Search Tree | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Dota2 Senate | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Hexspeak | Easy | Solution |
| 2 | Array Transformation | Easy | Solution |
| 2 | How Many Apples Can You Put into the Basket | Easy | Solution |
| 2 | Count Substrings with Only One Distinct Letter | Easy | Solution |
| 1 | Count Number of Homogenous Substrings | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 11 | Last Stone Weight | Easy | Solution |
| 6 | Maximal Square | Medium | Solution |
| 4 | Two Sum | Easy | Java, C++, Javascript |
| 4 | Subarray Sum Equals K | Medium | Solution |
| 4 | String Compression | Easy | Solution |
| 3 | Group Anagrams | Medium | Solution |
| 3 | Backspace String Compare | Easy | Solution |
| 3 | Minimum Moves to Equal Array Elements | Easy | Solution |
| 3 | Meeting Rooms II | Medium | Solution |
| 3 | Linked List Cycle | Easy | Solution |
| 3 | Search in Rotated Sorted Array | Medium | Solution |
| 2 | Add Two Numbers | Medium | Solution |
| 2 | Reverse Integer | Easy | Solution, C++ |
| 2 | Trapping Rain Water | Hard | Solution |
| 2 | Reverse Words in a String | Medium | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Longest Consecutive Sequence | Hard | Solution |
| 2 | Remove All Adjacent Duplicates in String II | Medium | Solution |
| 2 | Largest Number | Medium | Solution |
| 1 | Create Target Array in the Given Order | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 9 | Remove Colored Pieces if Both Neighbors are the Same Color | Medium | Java |
| 7 | 3Sum | Medium | Solution, C++ |
| 5 | Search in Rotated Sorted Array | Medium | Solution |
| 5 | Group Anagrams | Medium | Solution |
| 5 | Merge Intervals | Medium | Solution |
| 4 | Strange Printer | Hard | Solution |
| 4 | Best Time to Buy and Sell Stock II | Easy | Solution |
| 4 | LRU Cache | Hard | Solution |
| 3 | Two Sum | Easy | Java, C++, Javascript |
| 3 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 3 | Remove Nth Node From End of List | Medium | Solution |
| 3 | Generate Parentheses | Medium | Solution |
| 3 | Gas Station | Medium | Solution |
| 3 | Design HashMap | Easy | Solution |
| 3 | Best Time to Buy and Sell Stock | Easy | Solution |
| 3 | Degree of an Array | Easy | Solution |
| 2 | Maximum Subarray | Easy | Solution |
| 2 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| 2 | Reformat Date | Easy | Solution |
| 2 | Merge k Sorted Lists | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 20 | Add Strings | Easy | Solution |
| 9 | Subdomain Visit Count | Easy | Solution |
| 7 | Maximum Length of Repeated Subarray | Medium | Solution |
| 5 | Alert Using Same Key-Card Three or More Times in a One Hour Period | Medium | Solution |
| 4 | The Number of Full Rounds You Have Played | Medium | Solution |
| 4 | Course Schedule II | Medium | Solution |
| 3 | Valid Sudoku | Medium | Solution, Javascript |
| 2 | Max Chunks To Make Sorted | Medium | Solution |
| 2 | Valid Palindrome | Easy | Solution |
| 1 | Minimum Moves to Reach Target Score | Medium | Java |
| 1 | Delete Characters to Make Fancy String | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Minimum Number of Steps to Make Two Strings Anagram II | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Find Right Interval | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | K Inverse Pairs Array | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 6 | Add Two Numbers | Medium | Solution |
| 5 | Restore IP Addresses | Medium | Solution |
| 5 | 3Sum | Medium | Solution, C++ |
| 4 | Two Sum | Easy | Java, C++, Javascript |
| 4 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 4 | Top K Frequent Words | Medium | Solution |
| 4 | Roman to Integer | Easy | Solution |
| 4 | Intersection of Two Arrays II | Easy | Solution |
| 3 | Find All Anagrams in a String | Easy | Solution |
| 3 | Climbing Stairs | Easy | Solution |
| 3 | Pow(x, n) | Medium | Solution |
| 3 | First Unique Character in a String | Easy | Solution |
| 3 | LRU Cache | Hard | Solution |
| 3 | Merge Two Binary Trees | Easy | Solution |
| 3 | Valid Parenthesis String | Medium | Solution |
| 2 | Divide Two Integers | Medium | Solution |
| 2 | Group Anagrams | Medium | Solution |
| 2 | One Edit Distance | nan | Solution |
| 2 | 4 Sum | Medium | Solution |
| 2 | Palindrome Number | Easy | Java, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 8 | Maximize Distance to Closest Person | Easy | Solution |
| 6 | Move Zeroes | Easy | Solution |
| 6 | Zigzag Iterator | Medium | Solution |
| 6 | Summary Ranges | Medium | Solution |
| 4 | Permutation in String | Medium | Solution |
| 4 | Merge Intervals | Medium | Solution |
| 3 | Valid Parentheses | Easy | Solution |
| 3 | Merge k Sorted Lists | Hard | Solution |
| 3 | Reverse Linked List | Easy | Solution |
| 3 | Longest Subarray of 1's After Deleting One Element | Medium | Solution |
| 3 | Is Subsequence | Medium | Solution |
| 3 | String Compression | Easy | Solution |
| 3 | Max Stack | Hard | Solution |
| 3 | Number of Recent Calls | Easy | Solution |
| 2 | Number of Students Doing Homework at a Given Time | Easy | Solution |
| 2 | Line Reflection | Medium | Solution |
| 2 | Evaluate Reverse Polish Notation | Medium | Solution |
| 2 | Valid Palindrome | Easy | Solution |
| 2 | Reverse Words in a String III | Easy | Solution |
| 2 | Median of Two Sorted Arrays | Hard | Solution, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 5 | Destination City | Easy | Solution |
| 4 | Filter Restaurants by Vegan-Friendly, Price and Distance | Medium | Solution |
| 1 | Minimum Index Sum of Two Lists | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Day of the Year | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Verify Preorder Sequence in Binary Search Tree | Medium | Solution |
| 1 | N-Queens II | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Spiral Matrix | Medium | Solution |
| 2 | Two Sum | Easy | Java, C++, Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Two Sum | Easy | Java, C++, Javascript |
| 2 | K-diff Pairs in an Array | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Longest Substring Without Repeating Characters | Medium | Solution, C++ |
| 1 | Sort Even and Odd Indices Independently | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Two Sum | Easy | Java, C++, Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Rotate String | Easy | Solution |
| 3 | Fibonacci Number | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Reverse Nodes in k-Group | Hard | Solution |
| 2 | Two Sum | Easy | Java, C++, Javascript |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Reverse Nodes in Even Length Groups | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Group Anagrams | Medium | Solution |
| 3 | Reorganize String | Medium | Solution |
| 2 | Rotating the Box | Medium | Solution |
| 2 | Candy Crush | Medium | Solution |
| 2 | Odd Even Linked List | Medium | Solution |
| 2 | Implement Queue using Stacks | Medium | Solution |
| 2 | Number of Islands | Medium | Solution |
| 2 | Longest Consecutive Sequence | Hard | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Calculate Money in Leetcode Bank | Easy | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Check if Every Row and Column Contains All Numbers | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 2 | Jump Game II | Hard | Solution |
| 1 | Count Operations to Obtain Zero | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Coordinate With Maximum Network Quality | Medium | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Minimum Bit Flips to Convert Number | Easy | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Two Best Non-Overlapping Events | Medium | Java |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 4 | Move Zeroes | Easy | Solution |
| 3 | Reverse String | Easy | Solution |
| 2 | Contains Duplicate | Easy | Solution |
| 2 | Rotate Array | Easy | Solution |
| 2 | Best Time to Buy and Sell Stock | Easy | Solution |
| 2 | Valid Parentheses | Easy | Solution |
| 1 | Maximum Ascending Subarray Sum | Easy | Solution |
| 1 | Palindrome Partitioning IV | Hard | Solution |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 13 | Design a Stack With Increment Operation | Medium | Solution |
| 10 | Reformat Date | Easy | Solution |
| 8 | Maximum Swap | Medium | Solution |
| 7 | Course Schedule | Medium | Solution |
| 6 | LRU Cache | Hard | Solution |
| 6 | Split Array Largest Sum | Hard | Solution |
| 6 | Number of Islands | Medium | Solution |
| 6 | Spiral Matrix II | Medium | Solution |
| 6 | Binary Tree Maximum Path Sum | Hard | Solution |
| 5 | Gas Station | Medium | Solution |
| 5 | Decode String | Medium | Solution |
| 5 | Subarray Sum Equals K | Medium | Solution |
| 5 | Asteroid Collision | Medium | Solution |
| 5 | Walls and Gates | Medium | Solution |
| 5 | Roman to Integer | Easy | Solution |
| 4 | Path Sum III | Easy | Solution |
| 4 | Search in Rotated Sorted Array | Medium | Solution |
| 4 | Count Complete Tree Nodes | Medium | Solution |
| 4 | Evaluate Division | Medium | Solution |
| 4 | 3Sum | Medium | Solution, C++ |
| Occurence | Problem | Difficulty | Solution |
|---|---|---|---|
| 1 | Count Equal and Divisible Pairs in an Array | Easy | Java |