Roadmap All Tracks

Practice

106 hand-picked LeetCode problems, each mapped to the lesson that teaches its technique.

Easy

37 problems

Two Sum Arrays & Memory

Best Time to Buy and Sell Stock Arrays & Memory

Contains Duplicate Arrays & Memory

Valid Palindrome Strings

Reverse String Strings

Valid Anagram Strings

Longest Common Prefix Strings

Find the Index of the First Occurrence in a String Linear Search

Missing Number Linear Search

Majority Element Linear Search

Binary Search Binary Search

Search Insert Position Binary Search

First Bad Version Binary Search

Height Checker Bubble Sort

Merge Sorted Array Merge Sort

Sort Array By Parity Counting Sort

Valid Parentheses Stack

Implement Queue using Stacks Queue

Number of Recent Calls Queue

Moving Average from Data Stream Circular Queue

Reverse Linked List Linked List

Merge Two Sorted Lists Linked List

Linked List Cycle Linked List

Intersection of Two Arrays Sets

Happy Number Sets

Search in a Binary Search Tree Binary Search Tree

Binary Tree Inorder Traversal Tree Traversals

Binary Tree Preorder Traversal Tree Traversals

Last Stone Weight Heap & Priority Queue

Balanced Binary Tree AVL Tree

Convert Sorted Array to Binary Search Tree AVL Tree

Flood Fill Depth-First Search

Maximum Average Subarray I Sliding Window

Next Greater Element I Monotonic Stack

Assign Cookies Greedy Algorithms

Climbing Stairs Dynamic Programming

Fibonacci Number Recursion & the Call Stack

Medium

61 problems

Rotate Image 2D Arrays

Spiral Matrix 2D Arrays

Set Matrix Zeroes 2D Arrays

Number of Islands 2D Arrays

Find Minimum in Rotated Sorted Array Binary Search

Peak Index in a Mountain Array Ternary Search

Find Peak Element Ternary Search

Sort Colors Bubble Sort

Sort an Array Bubble Sort

Kth Largest Element in an Array Selection Sort

Insertion Sort List Insertion Sort

Top K Frequent Elements Heap Sort

Maximum Gap Radix Sort

Min Stack Stack

Evaluate Reverse Polish Notation Stack

Design Circular Queue Queue

Design Front Middle Back Queue Deque

Design Circular Deque Circular Queue

LRU Cache Doubly Linked List

Flatten a Multilevel Doubly Linked List Doubly Linked List

Design Browser History Doubly Linked List

Linked List Cycle II Circular Linked List

Insert into a Sorted Circular Linked List Circular Linked List

Group Anagrams Hash Map

Longest Consecutive Sequence Sets

Insert into a Binary Search Tree Binary Search Tree

Validate Binary Search Tree Binary Search Tree

Binary Tree Level Order Traversal Tree Traversals

Balance a Binary Search Tree AVL Tree

Range Sum Query - Mutable Segment Tree

Implement Trie (Prefix Tree) Trie (Prefix Tree)

Design Add and Search Words Data Structure Trie (Prefix Tree)

Rotting Oranges Breadth-First Search

Max Area of Island Depth-First Search

Course Schedule Topological Sort

Course Schedule II Topological Sort

Find Eventual Safe States Topological Sort

Network Delay Time Dijkstra's Shortest Path

Path with Maximum Probability Dijkstra's Shortest Path

Cheapest Flights Within K Stops Dijkstra's Shortest Path

Find the City With the Smallest Number of Neighbors Bellman–Ford

Shortest Path in Binary Matrix A* Search

Minimum Knight Moves A* Search

Number of Provinces Union-Find

Redundant Connection Union-Find

Accounts Merge Union-Find

Two Sum II - Input Array Is Sorted Two Pointers

Container With Most Water Two Pointers

Longest Substring Without Repeating Characters Sliding Window

Daily Temperatures Monotonic Stack

Non-overlapping Intervals Greedy Algorithms

Jump Game Greedy Algorithms

Minimum Number of Arrows to Burst Balloons Greedy Algorithms

Subsets Backtracking

Permutations Backtracking

Combination Sum Backtracking

Word Search Backtracking

Coin Change Dynamic Programming

House Robber Dynamic Programming

Longest Common Subsequence Dynamic Programming

Pow(x, n) Recursion & the Call Stack

Hard

8 problems

Count of Smaller Numbers After Self Merge Sort

Sliding Window Maximum Deque

Range Sum Query 2D - Mutable Segment Tree

Word Search II Trie (Prefix Tree)

Sliding Puzzle A* Search

Largest Rectangle in Histogram Monotonic Stack

Trapping Rain Water Monotonic Stack

N-Queens Backtracking