Lessons
Practice
Roadmap
Lessons
Practice
Roadmap
DS&A
System Design
Interview Questions
Level 1
0%
0/8 problems
Topics: Linked Lists
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Linked Lists
Problem
Difficulty
Solved
Linked List Cycle
Easy
Reverse Linked List
Easy
Palindrome Linked List
Easy
Merge Two Sorted Lists
Easy
Remove Nth Node From End of List
Medium
Reorder List
Medium
Copy List with Random Pointer
Medium
LRU Cache
Medium
Level 2
0%
0/13 problems
Topics: Stack, Two Pointers, Sliding Window
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Stack
Problem
Difficulty
Solved
Valid Parentheses
Easy
Min Stack
Medium
Evaluate Reverse Polish Notation
Medium
Daily Temperatures
Medium
Largest Rectangle in Histogram
Hard
Two Pointers
Problem
Difficulty
Solved
Valid Palindrome
Easy
Remove Duplicates from Sorted Array
Easy
3Sum
Medium
Container With Most Water
Medium
Sliding Window
Problem
Difficulty
Solved
Longest Substring Without Repeating Characters
Medium
Permutation in String
Medium
Minimum Window Substring
Hard
Sliding Window Maximum
Hard
Level 3
0%
0/8 problems
Topics: Binary Search, Merge Intervals
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Binary Search
Problem
Difficulty
Solved
Binary Search
Easy
First Bad Version
Easy
Search Insert Position
Easy
Search in Rotated Sorted Array
Medium
Find Minimum in Rotated Sorted Array
Medium
Median of Two Sorted Arrays
Hard
Merge Intervals
Problem
Difficulty
Solved
Merge Intervals
Medium
Insert Interval
Medium
Level 4
0%
0/8 problems
Topics: Arrays, Matrices
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Arrays
Problem
Difficulty
Solved
Two Sum
Easy
Best Time to Buy and Sell Stock
Easy
Maximum Subarray
Medium
Product of Array Except Self
Medium
Subarray Sum Equals K
Medium
Matrices
Problem
Difficulty
Solved
Set Matrix Zeroes
Medium
Spiral Matrix
Medium
Rotate Image
Medium
Level 5
0%
0/8 problems
Topics: Trees
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Trees
Problem
Difficulty
Solved
Maximum Depth of Binary Tree
Easy
Invert Binary Tree
Easy
Diameter of Binary Tree
Easy
Same Tree
Easy
Validate Binary Search Tree
Medium
Binary Tree Level Order Traversal
Medium
Lowest Common Ancestor of a Binary Tree
Medium
Serialize and Deserialize Binary Tree
Hard
Level 6
0%
0/8 problems
Topics: Heap / Priority Queue, K-way Merge, Top K Elements
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Heap / Priority Queue
Problem
Difficulty
Solved
Last Stone Weight
Easy
Task Scheduler
Medium
Find Median from Data Stream
Hard
K-way Merge
Problem
Difficulty
Solved
Kth Smallest Element in a Sorted Matrix
Medium
Merge k Sorted Lists
Hard
Top K Elements
Problem
Difficulty
Solved
Top K Frequent Elements
Medium
Kth Largest Element in an Array
Medium
Sort Characters By Frequency
Medium
Level 7
0%
0/13 problems
Topics: Divide and Conquer, Greedy, Backtracking
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Divide and Conquer
Problem
Difficulty
Solved
Sort List
Medium
Construct Binary Tree from Preorder and Inorder Traversal
Medium
Different Ways to Add Parentheses
Medium
Greedy
Problem
Difficulty
Solved
Jump Game
Medium
Jump Game II
Medium
Gas Station
Medium
Backtracking
Problem
Difficulty
Solved
Subsets
Medium
Subsets II
Medium
Permutations
Medium
Permutations II
Medium
Combination Sum
Medium
Word Search
Medium
N-Queens
Hard
Level 8
0%
0/11 problems
Topics: Graphs (Beginner), Graphs (Advanced)
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Graphs (Beginner)
Problem
Difficulty
Solved
Clone Graph
Medium
Number of Islands
Medium
Course Schedule
Medium
Pacific Atlantic Water Flow
Medium
Graphs (Advanced)
Problem
Difficulty
Solved
Course Schedule II
Medium
Network Delay Time
Medium
Path With Minimum Effort
Medium
Cheapest Flights Within K Stops
Medium
Shortest Path in Binary Matrix
Medium
Accounts Merge
Medium
Critical Connections in a Network
Hard
Level 9
0%
0/8 problems
Topics: Dynamic Programming
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Dynamic Programming
Problem
Difficulty
Solved
Climbing Stairs
Easy
House Robber
Medium
Longest Increasing Subsequence
Medium
Coin Change
Medium
Longest Common Subsequence
Medium
Word Break
Medium
Edit Distance
Medium
Regular Expression Matching
Hard