Learn DSA
Depth-First Search
Greedy Algorithms
Data Structures and Algorithms
A visual guide to the most important patterns and approaches for the coding interview.
This guide uses interactive visualizations to teach you the most important algorithm patterns for the coding interview.
Here's an example showing how a backtracking algorithm searches for the word HELLO:
word search backtracking
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Who is this for?
This is intended for those looking for a structured way to prepare for the coding interview in their preferred language. It assumes you understand how and why to use fundamental data structures such as arrays, dictionaries, and sets.
How do I use this?
Unless they are labeled with a Pre-Requisite, the patterns can be completed in any order. If you're short on time, start with Depth-First Search and Breadth-First Search, as they are the algorithms that most frequently show up during the coding interview.
Feeling confident?
Challenge yourself with a random problem
Done | Problem / Lesson | Difficulty |
|---|---|---|
Two Pointers (7 problems)0% | Lesson | |
Container With Most Water | Medium | |
3-Sum | Medium | |
Triangle Numbers | Medium | |
Move Zeroes | Easy | |
Sort Colors | Medium | |
Trapping Rain Water | Hard | |
Two Sum (Sorted) | Medium | |
Sliding Window (5 problems)0% | Lesson | |
Longest Substring Without Repeating Characters | Medium | |
Longest Repeating Character Replacement | Medium | |
Maximum Sum of Subarrays of Size K | Easy | |
Max Points You Can Obtain From Cards | Medium | |
Max Sum of Distinct Subarrays Length k | Medium | |
Intervals (5 problems)0% | Lesson | |
Can Attend Meetings | Easy | |
Insert Interval | Medium | |
Non-Overlapping Intervals | Medium | |
Merge Intervals | Medium | |
Employee Free Time | Hard | |
Stack (5 problems)0% | Lesson | |
Valid Parentheses | Easy | |
Decode String | Medium | |
Longest Valid Parentheses | Hard | |
Daily Temperatures | Medium | |
Largest Rectangle in Histogram | Hard | |
Linked List (5 problems)0% | Lesson | |
Linked List Cycle | Easy | |
Palindrome Linked List | Easy | |
Remove Nth Node From End of List | Medium | |
Reorder List | Medium | |
Swap Nodes in Pairs | Medium | |
Binary Search (2 problems)0% | Lesson | |
Apple Harvest (Koko Eating Bananas) | Medium | |
Search in Rotated Sorted Array | Medium | |
Heap (4 problems)0% | Lesson | |
Kth Largest Element in an Array | Medium | |
K Closest Points to Origin | Medium | |
Find K Closest Elements | Medium | |
Merge K Sorted Lists | Hard | |
Depth-First Search (13 problems)0% | Lesson | |
Maximum Depth of a Binary Tree | Easy | |
Path Sum | Easy | |
Validate Binary Search Tree | Medium | |
Calculate Tilt | Easy | |
Diameter of a Binary Tree | Easy | |
Path Sum II | Medium | |
Longest Univalue Path | Medium | |
Copy Graph | Easy | |
Graph Valid Tree | Medium | |
Flood Fill | Easy | |
Number of Islands | Medium | |
Surrounded Regions | Medium | |
Pacific Atlantic Water Flow | Medium | |
Breadth-First Search (8 problems)0% | Lesson | |
Level Order Sum | Easy | |
Rightmost Node | Medium | |
Zigzag Level Order | Medium | |
Maximum Width of Binary Tree | Medium | |
Minimum Knight Moves | Medium | |
Rotting Oranges | Medium | |
01-Matrix | Medium | |
Bus Routes | Hard | |
Backtracking (4 problems)0% | Lesson | |
Word Search | Medium | |
Subsets | Medium | |
Generate Parentheses | Medium | |
Combination Sum | Medium | |
Graphs (2 problems)0% | Lesson | |
Course Schedule | Medium | |
Course Schedule II | Medium | |
Dynamic Programming (7 problems)0% | Lesson | |
Counting Bits | Easy | |
Decode Ways | Medium | |
Maximal Square | Medium | |
Unique Paths | Medium | |
Longest Increasing Subsequence | Medium | |
Word Break | Medium | |
Maximum Profit in Job Scheduling | Medium | |
Greedy Algorithms (3 problems)0% | Lesson | |
Best Time to Buy and Sell Stock | Easy | |
Gas Station | Medium | |
Jump Game | Medium | |
Trie (2 problems)0% | Lesson | |
Implement Trie Methods | Medium | |
Prefix Matching | Medium | |
Prefix Sum (2 problems)0% | Lesson | |
Count Vowels in Substrings | Medium | |
Subarray Sum Equals K | Medium | |
Matrices (3 problems)0% | Lesson | |
Spiral Matrix | Medium | |
Rotate Image | Medium | |
Set Matrix Zeroes | Medium |