DSA | Frontend Beauty

The classic warm-up: find two indices that add to a target — brute force, hash map, and the follow-ups interviewers love.

beginner · Google · Amazon · Meta

Contains Duplicate

Contains Duplicate explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

Valid Anagram

Valid Anagram explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Group Anagrams

Group Anagrams explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Top K Frequent Elements

Top K Frequent Elements explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Product of Array Except Self

Product of Array Except Self explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Longest Consecutive Sequence

Longest Consecutive Sequence explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Valid Palindrome

Valid Palindrome explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

3Sum

3Sum explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Container With Most Water

Container With Most Water explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Best Time to Buy and Sell Stock

Best Time to Buy and Sell Stock explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Longest Substring Without Repeating

Longest Substring Without Repeating explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Longest Repeating Character Replacement

Longest Repeating Character Replacement explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Minimum Window Substring

Minimum Window Substring explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta

Valid Parentheses

Valid Parentheses explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Min Stack

Min Stack explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Evaluate Reverse Polish Notation

Evaluate Reverse Polish Notation explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Daily Temperatures

Daily Temperatures explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Car Fleet

Car Fleet explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Binary Search

Binary Search explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Search in Rotated Sorted Array

Search in Rotated Sorted Array explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Find Minimum in Rotated Sorted Array

Find Minimum in Rotated Sorted Array explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Time Based Key Value Store

Time Based Key Value Store explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Reverse Linked List

Reverse Linked List explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Merge Two Sorted Lists

Merge Two Sorted Lists explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Linked List Cycle

Linked List Cycle explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Reorder List

Reorder List explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Remove Nth Node From End

Remove Nth Node From End explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Copy List with Random Pointer

Copy List with Random Pointer explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Add Two Numbers Linked List

Add Two Numbers Linked List explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Find Duplicate Number

Find Duplicate Number explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

LRU Cache

LRU Cache explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta

Implement Trie

Implement Trie explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Design Add and Search Words

Design Add and Search Words explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Word Search II

Word Search II explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta · Amazon

Number of Islands

Number of Islands explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Clone Graph

Clone Graph explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Max Area of Island

Max Area of Island explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Pacific Atlantic Water Flow

Pacific Atlantic Water Flow explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta

Course Schedule

Course Schedule explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Course Schedule II

Course Schedule II explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Redundant Connection

Redundant Connection explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Word Ladder

Word Ladder explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta · Amazon

Climbing Stairs

Climbing Stairs explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

House Robber

House Robber explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

House Robber II

House Robber II explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Longest Palindromic Substring

Longest Palindromic Substring explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Coin Change

Coin Change explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Word Break

Word Break explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Longest Increasing Subsequence

Longest Increasing Subsequence explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Unique Paths

Unique Paths explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Jump Game

Jump Game explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Jump Game II

Jump Game II explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Gas Station

Gas Station explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Hand of Straights

Hand of Straights explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Merge Intervals

Merge Intervals explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Insert Interval

Insert Interval explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Non-overlapping Intervals

Non-overlapping Intervals explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Meeting Rooms

Meeting Rooms explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Meeting Rooms II

Meeting Rooms II explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Reverse Bits

Reverse Bits explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

Number of 1 Bits

Number of 1 Bits explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Counting Bits

Counting Bits explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Missing Number

Missing Number explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Sum of Two Integers

Sum of Two Integers explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Invert Binary Tree

Invert Binary Tree explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

Maximum Depth of Binary Tree

Maximum Depth of Binary Tree explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Same Tree

Same Tree explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

Subtree of Another Tree

Subtree of Another Tree explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta · Amazon

Lowest Common Ancestor BST

Lowest Common Ancestor BST explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Binary Tree Level Order

Binary Tree Level Order explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Validate Binary Search Tree

Validate Binary Search Tree explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Kth Smallest in BST

Kth Smallest in BST explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Construct Tree from Preorder Inorder

Construct Tree from Preorder Inorder explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta

Binary Tree Max Path Sum

Binary Tree Max Path Sum explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta

Serialize Deserialize Binary Tree

Serialize Deserialize Binary Tree explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta

Implement Queue with Stacks

Implement Queue with Stacks explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

Implement Stack with Queues

Implement Stack with Queues explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

beginner · Google · Meta

Sliding Window Maximum

Sliding Window Maximum explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta · Amazon

Find Median from Data Stream

Find Median from Data Stream explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta · Amazon

K Closest Points to Origin

K Closest Points to Origin explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Task Scheduler

Task Scheduler explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Design Twitter Lite

Design Twitter Lite explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta · Amazon

Encode and Decode Strings

Encode and Decode Strings explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Valid Sudoku

Valid Sudoku explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Spiral Matrix

Spiral Matrix explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Rotate Image

Rotate Image explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Set Matrix Zeroes

Set Matrix Zeroes explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Word Search

Word Search explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Subsets

Subsets explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Combination Sum

Combination Sum explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

Permutations

Permutations explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta

N-Queens

N-Queens explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

advanced · Google · Meta · Amazon

Palindrome Partitioning

Palindrome Partitioning explained for frontend engineers — mental model, examples, common mistakes, and interview tips.

intermediate · Google · Meta · Amazon

Letter Combinations Phone Number