📘 Collection of 225 leetcode problems. Includes solutions and quizzes/questions/tests in flashcards format (Anki) to learn patterns/techniques.
- 🚀 NeetCode
🅱️ Blind- 🥇 LeetCode
- 🧩 Sean Prashad
- 🏫 Tech interview handbook
- 🧑💻 Hackernoon
Disclaimer: Some of the questions are taken from neetcode.io/practice, only the questions that correspond to the "free" category were used, the content belongs to neetcode and is only being used for educational purposes.
The questions in this section are designed to help you remember the patterns or techniques used throughout the problems. The problems are in a Q&A format, this is to facilitate the creation of a deck of Anki cards.
The order is based on the roadmap created by neetcode
| Symbol | Meaning |
|---|---|
| ✅ | Transcribed/created questions (may need revision) |
| 📘 | Questions that may need to be transcribed |
| Questions that do not appear on neetcode.io or are behind a paywall and need to be created | |
| [Blind] | Question part of Blind 75 original post |
| [Ex] | Extra question that is not in that category in neetcode.io/roadmap |
| [ComEx] | Extra question considered within blind by the community |
◽ - Dynamic Arrays - Data Structures & Algorithms for Beginners
◽ - Hash Usage - Data Structures & Algorithms for Beginners
◽ - Hash Implementation - Data Structures & Algorithms for Beginners
◽ - Prefix Sums - Advanced Algorithms
◽ - Two Pointers - Advanced Algorithms
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0125 | Valid Palindrome - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0167 | Two Sum II Input Array Is Sorted | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅ |
| 0015 | 3Sum - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0011 | Container With Most Water - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0042 | Trapping Rain Water | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Stacks - Data Structures & Algorithms for Beginners
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0020 | Valid Parentheses - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0155 | Min Stack | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0150 | Evaluate Reverse Polish Notation | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0022 | Generate Parentheses | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0739 | Daily Temperatures | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0853 | Car Fleet | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0084 | Largest Rectangle In Histogram | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Search Array - Data Structures & Algorithms for Beginners
◽ - Search Range - Data Structures & Algorithms for Beginners
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0704 | Binary Search | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0074 | Search a 2D Matrix | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0875 | Koko Eating Bananas | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0153 | Find Minimum In Rotated Sorted Array - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0033 | Search In Rotated Sorted Array - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0981 | Time Based Key Value Store | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0004 | Median of Two Sorted Arrays | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Sliding Window Fixed Size - Advanced Algorithms
◽ - Sliding Window Variable Size - Advanced Algorithms
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0121 | Best Time to Buy And Sell Stock - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0003 | Longest Substring Without Repeating Characters - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0424 | Longest Repeating Character Replacement - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0567 | Permutation In String | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0076 | Minimum Window Substring - [Blind] | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0239 | Sliding Window Maximum | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Singly Linked Lists - Data Structures & Algorithms for Beginners
◽ - Doubly Linked Lists - Data Structures & Algorithms for Beginners
◽ - Fast and Slow Pointers - Advanced Algorithms
◽ - BST Insert and Remove - Data Structures & Algorithms for Beginners
◽ - Depth-First Search - Data Structures & Algorithms for Beginners
◽ - Breadth-First Search - Data Structures & Algorithms for Beginners
◽ - BST Sets and Maps - Data Structures & Algorithms for Beginners
◽ - Iterative DFS - Advanced Algorithms
◽ - Trie - Advanced Algorithms
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0208 | Implement Trie Prefix Tree - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0211 | Design Add And Search Words Data Structure - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0212 | Word Search II - [Blind] | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Tree Maze - Data Structures & Algorithms for Beginners
◽ - Subsets - Advanced Algorithms
◽ - Combinations - Advanced Algorithms
◽ - Permutations - Advanced Algorithms
◽ - Heap Properties - Data Structures & Algorithms for Beginners
◽ - Push and Pop - Data Structures & Algorithms for Beginners
◽ - Heapify - Data Structures & Algorithms for Beginners
◽ - Two Heaps - Advanced Algorithms
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0703 | Kth Largest Element In a Stream | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 1046 | Last Stone Weight | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0973 | K Closest Points to Origin | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0215 | Kth Largest Element In An Array | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0621 | Task Scheduler | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0355 | Design Twitter | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0295 | Find Median From Data Stream - [Blind] | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Intro to Graphs - Data Structures & Algorithms for Beginners
◽ - Matrix DFS - Data Structures & Algorithms for Beginners
◽ - Matrix BFS - Data Structures & Algorithms for Beginners
◽ - Adjacency List - Data Structures & Algorithms for Beginners
◽ - 1-Dimension DP - Data Structures & Algorithms for Beginners
◽ - Palindromes - Advanced Algorithms
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0057 | Insert Interval - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0056 | Merge Intervals - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0435 | Non Overlapping Intervals - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0252 | Meeting Rooms - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 0253 | Meeting Rooms II - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | ✅📘 |
| 1851 | Minimum Interval to Include Each Query | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - Kadane's Algorithm - Advanced Algorithms
◽ - Dijkstra's - Advanced Algorithms
◽ - Prim's - Advanced Algorithms
◽ - Kruskal's - Advanced Algorithms
◽ - Topological Sort - Advanced Algorithms
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0332 | Reconstruct Itinerary | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 1584 | Min Cost to Connect All Points | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0743 | Network Delay Time | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0778 | Swim In Rising Water | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0269 | Alien Dictionary - [Blind] | Link | Hard | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0787 | Cheapest Flights Within K Stops | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |
◽ - 2-Dimension DP - Data Structures & Algorithms for Beginners
◽ - 0 / 1 Knapsack - Advanced Algorithms
◽ - Unbounded Knapsack - Advanced Algorithms
◽ - LCS - Advanced Algorithms
◽ - Bit Operations - Data Structures & Algorithms for Beginners
| # | Title - NeetCode | LeetCode | Difficulty | Video Solution | Code Solution (may or may not exist) | Time | Space | Anki |
|---|---|---|---|---|---|---|---|---|
| 0136 | Single Number | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0191 | Number of 1 Bits - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0338 | Counting Bits - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0190 | Reverse Bits - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0268 | Missing Number - [Blind] | Link | Easy | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0371 | Sum of Two Integers - [Blind] | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A | |
| 0007 | Reverse Integer | Link | Medium | YouTube | C C++ C# Dart GO Java JS Kotlin Python Ruby Rust Scala Swift TS | N/A | N/A |