Interview Question Library

System Design

Design a URL Shortener (Medium)
Design Ticketmaster (Hard)
Design WhatsApp (Hard)
Design a Distributed Rate Limiter (Medium)
Design a News Feed (Hard)
Design Uber (Hard)
Design a Web Crawler (Medium)
Design Top-K Trending Videos (Hard)
Design Dropbox (Medium)
Design YouTube (Hard)
Design Google Docs (Hard)
Design a Payment System (Hard)
Design a Notification System (Medium)
Design a Distributed Cache (Medium)
Design a Distributed Job Scheduler (Hard)
Design Search Autocomplete (Medium)
Design a Chat LLM Serving Platform (Hard)
Design an Ad Click Aggregator (Hard)
Design Yelp (Proximity Search) (Medium)
Design an Online Auction (Medium)
Design Slack (Hard)
Design Google Calendar (Medium)
Design Google Maps (Hard)
Design Online Chess (Medium)
Design LeetCode (Medium)
Design an Online Bookstore (Medium)
Design Meta Post Privacy (Hard)
Design Airbnb (Hard)
Design DoorDash (Food Delivery) (Hard)
Design Spotify (Medium)
Design Zoom (Video Conferencing) (Hard)
Design Figma (Multiplayer Editing) (Hard)
Design Cash App (P2P Payments) (Hard)
Design Instagram (Medium)
Design Twitter Search (Hard)
Design Reddit (Medium)
Design TikTok (For You Feed) (Hard)
Design a Flash Sale System (Hard)
Design GitHub (Hard)
Design Gmail (Hard)
Design Tinder (Medium)
Design Facebook Live Comments (Medium)
Design Strava (Medium)
Design a Price Tracker (Medium)
Design Google News (Hard)
Design a CI/CD System (Hard)
Design a Webhook Delivery System (Medium)
Design a Distributed File System (Hard)
Design Distributed Counters (Medium)
Design a Real-Time Leaderboard (Medium)
Design a Remote Devbox (Hard)
Design a Crossword Puzzle Solver (Hard)
Design Smart Grid Device Control (Hard)
Design a Stock Exchange (Hard)
Design a Real-Time Market Data Feed (Hard)
Design a Content Delivery Network (CDN) (Hard)
Design a Distributed Key-Value Store (Hard)
Design a Distributed Message Queue (Hard)
Design a Metrics Monitoring & Alerting System (Medium)
Design Over-the-Air (OTA) Firmware Updates (Medium)
Design an Enterprise Data Integration Platform (Hard)
Design Pastebin (Easy)
Design a Distributed Lock Service (Hard)
Design ChatGPT Playground (Medium)
Design a Batch Inference System (Hard)
Design ML Model Distribution (Hard)
Design Sora (Text-to-Video) (Hard)
Design a Data Labeling Platform (Medium)

Arrays & Strings

Longest Substring Without Repeating Characters (Medium)
Minimum Window Substring (Hard)
Trapping Rain Water (Hard)
Container With Most Water (Medium)
3Sum (Medium)
Maximum Subarray (Kadane's Algorithm) (Medium)
Product of Array Except Self (Medium)
Sort Colors (Dutch National Flag) (Medium)
Majority Element (Boyer–Moore Vote) (Easy)
Corporate Flight Bookings (Difference Array) (Medium)
Find the Duplicate Number (Medium)
Find All Anagrams in a String (Medium)
Longest Palindromic Substring (Medium)
Find the First Occurrence (KMP) (Medium)
Best Time to Buy and Sell Stock (Easy)
Valid Palindrome (Easy)
Valid Palindrome II (Easy)
Valid Word Abbreviation (Easy)
Merge Sorted Array (Easy)
Move Zeroes (Easy)
Longest Common Prefix (Easy)
Rotate Image (Medium)
Spiral Matrix (Medium)
Next Permutation (Medium)
Set Matrix Zeroes (Medium)
Longest Repeating Character Replacement (Medium)
Max Consecutive Ones III (Medium)
Minimum Size Subarray Sum (Medium)
First Missing Positive (Hard)
Text Justification (Hard)
Remove Duplicates from Sorted Array (Easy)
Rotate Array (Medium)
Squares of a Sorted Array (Easy)
Two Sum II - Input Array Is Sorted (Medium)
Zigzag Conversion (Medium)
4Sum (Medium)
3Sum Closest (Medium)
Fruit Into Baskets (Medium)
Permutation in String (Medium)
String Compression (Medium)
Reverse Words in a String (Medium)
Subarray Product Less Than K (Medium)
Game of Life (Medium)
Majority Element II (Medium)
Remove Element (Easy)
Merge Strings Alternately (Easy)
Maximum Average Subarray I (Easy)
Is Subsequence (Easy)
Reverse Vowels of a String (Easy)
Maximum Product of Three Numbers (Easy)
Remove Duplicates from Sorted Array II (Medium)
Diagonal Traverse (Medium)
Spiral Matrix II (Medium)
Increasing Triplet Subsequence (Medium)
Frequency of the Most Frequent Element (Medium)
Maximum Points You Can Obtain from Cards (Medium)
Number of Substrings Containing All Three Characters (Medium)
Substring with Concatenation of All Words (Hard)
Rotate String (Easy)
Longest Substring with At Least K Repeating Characters (Medium)
Reverse Pairs (Hard)
Find Pivot Index (Easy)
Rearrange Array Elements by Sign (Medium)
Count Binary Substrings (Easy)
Can Make Arithmetic Progression From Sequence (Easy)
Find Missing and Repeated Values (Easy)
Find All Numbers Disappeared in an Array (Easy)
Valid Triangle Number (Medium)
Third Maximum Number (Easy)
Maximum Sum of Distinct Subarrays With Length K (Medium)
Maximum Number of Vowels in a Substring of Given Length (Medium)
Shortest Unsorted Continuous Subarray (Medium)
Longest Substring with At Most K Distinct Characters (Medium)
Longest Mountain in Array (Medium)
Sort an Array (Medium)
Toeplitz Matrix (Easy)
Range Sum Query - Immutable (Easy)
Range Sum Query 2D - Immutable (Medium)
Product of the Last K Numbers (Medium)

Hashing

Subarray Sum Equals K (Medium)
In-Memory Database (Multi-Part) (Hard)
Implement an LRU Cache (Medium)
Two Sum (Easy)
Group Anagrams (Medium)
Longest Consecutive Sequence (Medium)
Contains Nearby Duplicate (Easy)
Contiguous Array (Equal 0s and 1s) (Medium)
First Unique Character (Easy)
Valid Anagram (Easy)
Isomorphic Strings (Easy)
Valid Sudoku (Medium)
Continuous Subarray Sum (Medium)
Subarray Sums Divisible by K (Medium)
Happy Number (Easy)
Logger Rate Limiter (Easy)
Contains Duplicate (Easy)
Ransom Note (Easy)
Word Pattern (Easy)
Design HashMap (Easy)
Count Number of Nice Subarrays (Medium)
Binary Subarrays With Sum (Medium)
LFU Cache (Hard)
Intersection of Two Arrays (Easy)
Repeated DNA Sequences (Medium)
Group Shifted Strings (Medium)
Design Underground System (Medium)
Find All Duplicates in an Array (Medium)
Longest Palindrome (Easy)
Invalid Transactions (Medium)
Analyze User Website Visit Pattern (Medium)
Unique Number of Occurrences (Easy)
Subarrays with K Different Integers (Hard)
Brick Wall (Medium)
K-diff Pairs in an Array (Medium)
Max Number of K-Sum Pairs (Medium)
Jewels and Stones (Easy)
Find Common Characters (Easy)
Shortest Word Distance (Easy)
Shortest Word Distance II (Medium)
Sort Array by Increasing Frequency (Easy)

Linked Lists

Reverse a Linked List (Easy)
Reverse a Sublist (Medium)
Detect a Cycle (Floyd's Algorithm) (Easy)
Find the Cycle Entry (Medium)
Middle of a Linked List (Easy)
Merge Two Sorted Lists (Easy)
Merge K Sorted Lists (Hard)
Remove the Nth Node From the End (Medium)
Reorder List (Medium)
Palindrome Linked List (Easy)
Add Two Numbers (Medium)
Swap Nodes in Pairs (Medium)
Rotate List (Medium)
Odd Even Linked List (Medium)
Remove Duplicates from Sorted List II (Medium)
Sort List (Medium)
Reverse Nodes in k-Group (Hard)
Remove Duplicates from Sorted List (Easy)
Remove Linked List Elements (Easy)
Partition List (Medium)
Delete the Middle Node of a Linked List (Medium)
Add Two Numbers II (Medium)
Insertion Sort List (Medium)
Next Greater Node In Linked List (Medium)
Swapping Nodes in a Linked List (Medium)
Maximum Twin Sum of a Linked List (Medium)
Design Linked List (Medium)
Merge Nodes in Between Zeros (Medium)
Merge In Between Linked Lists (Medium)
Remove Zero Sum Consecutive Nodes from Linked List (Medium)
Reverse Nodes in Even Length Groups (Medium)
Linked List Components (Medium)
Double a Number Represented as a Linked List (Medium)

Stack & Monotonic Stack

Daily Temperatures (Medium)
Valid Parentheses (Easy)
Min Stack (Medium)
Evaluate Reverse Polish Notation (Medium)
Basic Calculator II (Medium)
Next Greater Element (Circular) (Medium)
Largest Rectangle in Histogram (Hard)
Online Stock Span (Medium)
Remove K Digits (Medium)
Minimum Remove to Make Valid Parentheses (Medium)
Decode String (Medium)
Asteroid Collision (Medium)
Simplify Path (Medium)
Basic Calculator (Hard)
Longest Valid Parentheses (Hard)
Sum of Subarray Minimums (Medium)
Next Greater Element I (Easy)
Final Prices With a Special Discount in a Shop (Easy)
Remove All Adjacent Duplicates in String (Easy)
Remove All Adjacent Duplicates in String II (Medium)
Implement Queue using Stacks (Easy)
Minimum Add to Make Parentheses Valid (Medium)
132 Pattern (Medium)
Remove Duplicate Letters (Medium)
Maximal Rectangle (Hard)
Exclusive Time of Functions (Medium)
Car Fleet (Medium)
Buildings With an Ocean View (Medium)
Backspace String Compare (Easy)
Baseball Game (Easy)
Number of Visible People in a Queue (Hard)
Basic Calculator III (Hard)
Max Stack (Hard)
Design Browser History (Medium)
Sum of Subarray Ranges (Medium)
Maximum Width Ramp (Medium)
Remove Outermost Parentheses (Easy)
Maximum Nesting Depth of the Parentheses (Easy)
Design a Stack With Increment Operation (Medium)
Maximum Frequency Stack (Hard)
Score of Parentheses (Medium)
Using a Robot to Print the Lexicographically Smallest String (Medium)

Queue & Deque

Sliding Window Maximum (Hard)
Rotting Oranges (Multi-source BFS) (Medium)
Distance to Nearest Zero (01 Matrix) (Medium)
Binary Tree Level Order Traversal (Medium)
Open the Lock (Medium)
Number of Recent Calls (Easy)
Shortest Subarray With Sum at Least K (Hard)
Design Hit Counter (Medium)
Design Circular Queue (Medium)
Shortest Path in Binary Matrix (Medium)
Walls and Gates (Medium)
Longest Subarray With Absolute Diff ≤ Limit (Medium)
Bus Routes (Hard)
Moving Average from Data Stream (Easy)
Implement Stack using Queues (Easy)
First Unique Number (Medium)
Find the Winner of the Circular Game (Medium)
Jump Game VII (Medium)
Shortest Path in a Grid with Obstacles Elimination (Hard)
Number of Students Unable to Eat Lunch (Easy)
Time Needed to Buy Tickets (Easy)
Dota2 Senate (Medium)
Nearest Exit from Entrance in Maze (Medium)
Snakes and Ladders (Medium)
Minimum Knight Moves (Medium)
The Maze (Medium)
Shortest Distance from All Buildings (Hard)
Minimum Genetic Mutation (Medium)
Shortest Path to Get All Keys (Hard)
Find the Safest Path in a Grid (Medium)
Continuous Subarrays (Medium)
Count Subarrays With Fixed Bounds (Hard)

Heap & Priority Queue

Top K Frequent Elements (Medium)
Find Median from Data Stream (Hard)
Kth Largest Element in an Array (Medium)
K Closest Points to Origin (Medium)
Kth Largest Element in a Stream (Easy)
Task Scheduler (Medium)
Last Stone Weight (Easy)
IPO: Maximize Capital (Hard)
Single-Threaded CPU Scheduling (Medium)
Top K Frequent Words (Medium)
Sort Characters by Frequency (Medium)
Kth Smallest Element in a Sorted Matrix (Medium)
Furthest Building You Can Reach (Medium)
Maximum Number of Events That Can Be Attended (Medium)
Meeting Rooms III (Hard)
Minimum Number of Refueling Stops (Hard)
Smallest Range Covering Elements from K Lists (Hard)
Design Twitter (Medium)
Seat Reservation Manager (Medium)
Total Cost to Hire K Workers (Medium)
Process Tasks Using Servers (Medium)
Find K Pairs with Smallest Sums (Medium)
Ugly Number II (Medium)
Minimum Cost to Hire K Workers (Hard)
Maximum Performance of a Team (Hard)
Design A Leaderboard (Medium)
Exam Room (Medium)
K-th Smallest Prime Fraction (Medium)
Stock Price Fluctuation (Medium)
Design Task Manager (Medium)
Find Score of an Array After Marking All Elements (Medium)
Maximal Score After Applying K Operations (Medium)
Number of Orders in the Backlog (Medium)

Binary Search

Search in Rotated Sorted Array (Medium)
Minimum Eating Speed (Medium)
Time-Based Key-Value Store (Medium)
Binary Search (Easy)
Search Insert Position (Lower Bound) (Easy)
First and Last Position in a Sorted Array (Medium)
Find Minimum in Rotated Sorted Array (Medium)
Capacity to Ship Packages Within D Days (Medium)
Find a Peak Element (Medium)
Split Array Largest Sum (Hard)
Median of Two Sorted Arrays (Hard)
Search a 2D Matrix (Medium)
Sqrt(x) (Easy)
Single Element in a Sorted Array (Medium)
Kth Missing Positive Number (Easy)
Find K Closest Elements (Medium)
Minimum Number of Days to Make m Bouquets (Medium)
Search a 2D Matrix II (Medium)
Peak Index in a Mountain Array (Medium)
Search in Rotated Sorted Array II (Medium)
Find the Smallest Divisor Given a Threshold (Medium)
Snapshot Array (Medium)
Valid Perfect Square (Easy)
Magnetic Force Between Two Balls (Medium)
H-Index II (Medium)
Find a Peak Element II (Medium)
Heaters (Medium)
Arranging Coins (Easy)
Maximum Candies Allocated to K Children (Medium)
Kth Smallest Number in Multiplication Table (Hard)
Find K-th Smallest Pair Distance (Hard)
Find Smallest Letter Greater Than Target (Easy)
Count Negative Numbers in a Sorted Matrix (Easy)
Successful Pairs of Spells and Potions (Medium)
Minimum Time to Complete Trips (Medium)
Minimized Maximum of Products Distributed to Any Store (Medium)
Minimum Speed to Arrive on Time (Medium)

Trees

Lowest Common Ancestor of a Binary Tree (Medium)
Binary Tree Right Side View (Medium)
Maximum Depth of a Binary Tree (Easy)
Invert a Binary Tree (Easy)
Balanced Binary Tree (Easy)
Diameter of a Binary Tree (Easy)
Path Sum II (Medium)
Binary Tree Maximum Path Sum (Hard)
Construct a Tree From Preorder and Inorder (Medium)
Binary Tree Inorder Traversal (Iterative) (Easy)
House Robber III (Tree DP) (Medium)
Same Tree (Easy)
Symmetric Tree (Easy)
Subtree of Another Tree (Easy)
Binary Tree Zigzag Level Order Traversal (Medium)
Binary Tree Vertical Order Traversal (Medium)
All Nodes Distance K in Binary Tree (Medium)
Sum Root to Leaf Numbers (Medium)
Path Sum III (Medium)
Maximum Width of Binary Tree (Medium)
Flatten Binary Tree to Linked List (Medium)
Amount of Time for Binary Tree to Be Infected (Medium)
Boundary of Binary Tree (Medium)
Step-By-Step Directions From a Binary Tree Node to Another (Medium)
Vertical Order Traversal of a Binary Tree (Hard)
Count Good Nodes in Binary Tree (Medium)
Find Leaves of Binary Tree (Medium)
Binary Tree Cameras (Hard)
Binary Tree Paths (Easy)
Minimum Depth of Binary Tree (Easy)
Path Sum (Easy)
Count Complete Tree Nodes (Easy)
Create Binary Tree From Descriptions (Medium)
Count Nodes Equal to Average of Subtree (Medium)
Cousins in Binary Tree (Easy)
Maximum Difference Between Node and Ancestor (Medium)
Longest ZigZag Path in a Binary Tree (Medium)
Binary Tree Preorder Traversal (Easy)
Sum of Left Leaves (Easy)
Merge Two Binary Trees (Easy)
Find Largest Value in Each Tree Row (Medium)
Check Completeness of a Binary Tree (Medium)
Construct Binary Tree from Inorder and Postorder Traversal (Medium)
Maximum Level Sum of a Binary Tree (Medium)
Binary Tree Tilt (Easy)

Binary Search Trees

Search in a Binary Search Tree (Easy)
Validate a Binary Search Tree (Medium)
Kth Smallest Element in a BST (Medium)
Lowest Common Ancestor in a BST (Medium)
Insert Into a Binary Search Tree (Medium)
Delete a Node in a BST (Medium)
Range Sum of a BST (Easy)
Convert a Sorted Array to a Balanced BST (Easy)
Two Sum IV - Input is a BST (Easy)
Closest Binary Search Tree Value (Easy)
Trim a Binary Search Tree (Medium)
Inorder Successor in BST (Medium)
Recover Binary Search Tree (Medium)
Convert Sorted List to Binary Search Tree (Medium)
Convert BST to Greater Tree (Medium)
Minimum Absolute Difference in BST (Easy)
Closest Binary Search Tree Value II (Hard)
Balance a Binary Search Tree (Medium)
Unique Binary Search Trees (Medium)
Construct Binary Search Tree from Preorder Traversal (Medium)
Increasing Order Search Tree (Easy)
Find Mode in Binary Search Tree (Easy)
All Elements in Two Binary Search Trees (Medium)
Largest BST Subtree (Medium)
Count of Smaller Numbers After Self (Hard)
Two Sum BSTs (Medium)
Verify Preorder Sequence in Binary Search Tree (Medium)
Maximum Sum BST in Binary Tree (Hard)
Closest Nodes Queries in a Binary Search Tree (Medium)
Contains Duplicate III (Hard)

Graphs

Number of Islands (Medium)
Course Schedule (Ordering) (Medium)
Network Delay Time (Medium)
Accounts Merge (Medium)
Number of Provinces (Connected Components) (Medium)
Redundant Connection (Medium)
Graph Valid Tree (Medium)
Word Ladder (Hard)
Cheapest Flights Within K Stops (Bellman–Ford) (Medium)
City With the Fewest Reachable Neighbors (Floyd–Warshall) (Medium)
Min Cost to Connect All Points (MST) (Medium)
Path With Minimum Effort (Dijkstra) (Medium)
Pacific Atlantic Water Flow (Medium)
Is Graph Bipartite? (Medium)
Course Schedule II (Medium)
Max Area of Island (Medium)
Flood Fill (Easy)
Surrounded Regions (Medium)
Number of Connected Components in an Undirected Graph (Medium)
Making A Large Island (Hard)
Reconstruct Itinerary (Hard)
Alien Dictionary (Hard)
Keys and Rooms (Medium)
Find Eventual Safe States (Medium)
Possible Bipartition (Medium)
Swim in Rising Water (Hard)
The Earliest Moment When Everyone Become Friends (Medium)
Parallel Courses III (Hard)
Number of Islands II (Hard)
Minimum Height Trees (Medium)
Find if Path Exists in Graph (Easy)
Find the Celebrity (Medium)
All Paths From Source to Target (Medium)
Most Stones Removed with Same Row or Column (Medium)
Number of Distinct Islands (Medium)
Critical Connections in a Network (Hard)
Shortest Bridge (Medium)
Reorder Routes to Make All Paths Lead to the City Zero (Medium)
Number of Operations to Make Network Connected (Medium)
Island Perimeter (Easy)
Detonate the Maximum Bombs (Medium)
Find All Possible Recipes from Given Supplies (Medium)
Parallel Courses (Medium)
Minimum Fuel Cost to Report to the Capital (Medium)
Detect Cycles in 2D Grid (Medium)
Find the Town Judge (Easy)
Minimize Malware Spread (Hard)
Count Unreachable Pairs of Nodes in an Undirected Graph (Medium)

Dynamic Programming

Coin Change (Medium)
Longest Increasing Subsequence (Medium)
Word Break (Medium)
Edit Distance (Hard)
Climbing Stairs (Easy)
House Robber (Medium)
Decode Ways (Medium)
Unique Paths (Medium)
Minimum Path Sum (Medium)
Longest Common Subsequence (Medium)
Longest Palindromic Subsequence (Medium)
0/1 Knapsack (Medium)
Coin Change II (Unbounded Knapsack) (Medium)
Partition Equal Subset Sum (Medium)
Target Sum (Medium)
Matrix Chain Multiplication (Hard)
Burst Balloons (Hard)
Palindrome Partitioning II (Min Cuts) (Hard)
Best Time to Buy and Sell Stock With Cooldown (Medium)
Best Time to Buy and Sell Stock IV (k Transactions) (Hard)
Maximum Product Subarray (Medium)
Palindromic Substrings (Medium)
House Robber II (Medium)
Unique Paths II (Medium)
Maximal Square (Medium)
Interleaving String (Medium)
Regular Expression Matching (Hard)
Maximum Profit in Job Scheduling (Hard)
Longest Increasing Path in a Matrix (Hard)
Min Cost Climbing Stairs (Easy)
Pascal's Triangle (Easy)
Triangle (Medium)
Perfect Squares (Medium)
Minimum Cost For Tickets (Medium)
Predict the Winner (Medium)
Maximum Sum Circular Subarray (Medium)
Wildcard Matching (Hard)
Distinct Subsequences (Hard)
Russian Doll Envelopes (Hard)
Best Time to Buy and Sell Stock III (Hard)
Best Time to Buy and Sell Stock with Transaction Fee (Medium)
Combination Sum IV (Medium)
Number of Longest Increasing Subsequence (Medium)
Minimum Falling Path Sum (Medium)
Dungeon Game (Hard)
Frog Jump (Hard)
Delete and Earn (Medium)
Integer Break (Medium)
Partition Array for Maximum Sum (Medium)
Minimum Difficulty of a Job Schedule (Hard)
Minimum Cost to Cut a Stick (Hard)
Fibonacci Number (Easy)
Count Square Submatrices with All Ones (Medium)
Domino and Tromino Tiling (Medium)
Cherry Pickup (Hard)
Longest String Chain (Medium)
Number of Ways to Form a Target String Given a Dictionary (Hard)
Painting the Walls (Hard)
New 21 Game (Medium)
Stone Game III (Hard)
Maximum Sum of 3 Non-Overlapping Subarrays (Hard)

Backtracking

Generate Subsets and Permutations (Medium)
Permutations (Medium)
Combinations (Medium)
Combination Sum (Medium)
N-Queens (Hard)
Sudoku Solver (Hard)
Word Search (Medium)
Generate Parentheses (Medium)
Letter Combinations of a Phone Number (Medium)
Subsets II (Medium)
Combination Sum II (Medium)
Permutations II (Medium)
Palindrome Partitioning (Medium)
Restore IP Addresses (Medium)
Word Break II (Hard)
Expression Add Operators (Hard)
Subsets (Medium)
Combination Sum III (Medium)
Letter Case Permutation (Medium)
Matchsticks to Square (Medium)
Remove Invalid Parentheses (Hard)
Word Ladder II (Hard)
24 Game (Hard)
Beautiful Arrangement (Medium)
Path with Maximum Gold (Medium)
Maximum Length of a Concatenated String with Unique Characters (Medium)
Generalized Abbreviation (Medium)
Factor Combinations (Medium)
Optimal Account Balancing (Hard)
Unique Paths III (Hard)
N-Queens II (Hard)
Different Ways to Add Parentheses (Medium)
The k-th Lexicographical String of All Happy Strings of Length n (Medium)
Shopping Offers (Medium)

Greedy

Jump Game (Medium)
Jump Game II (Minimum Jumps) (Medium)
Gas Station (Medium)
Partition Labels (Medium)
Fractional Knapsack (Medium)
Minimum Cost to Connect Sticks (Huffman) (Medium)
Candy (Hard)
Activity Selection (Max Meetings in One Room) (Medium)
Best Time to Buy and Sell Stock II (Medium)
Can Place Flowers (Easy)
Valid Parenthesis String (Medium)
Largest Number (Medium)
Boats to Save People (Medium)
Hand of Straights (Medium)
Maximum Swap (Medium)
Lemonade Change (Easy)
Assign Cookies (Easy)
Two City Scheduling (Medium)
Queue Reconstruction by Height (Medium)
Minimum Deletions to Make Character Frequencies Unique (Medium)
Maximum Units on a Truck (Easy)
Maximize Distance to Closest Person (Medium)
Reduce Array Size to The Half (Medium)
Wiggle Subsequence (Medium)
Bag of Tokens (Medium)
Minimum Number of Taps to Open to Water a Garden (Hard)
Broken Calculator (Medium)
Minimum Initial Energy to Finish Tasks (Hard)
Maximum Ice Cream Bars (Medium)
Maximum Element After Decreasing and Rearranging (Medium)
Minimum Number of Increments on Subarrays to Form a Target Array (Hard)
Move Pieces to Obtain a String (Medium)
Partitioning Into Minimum Number Of Deci-Binary Numbers (Medium)

Intervals

Merge Overlapping Intervals (Medium)
Minimum Meeting Rooms (Medium)
Insert Interval (Medium)
Meeting Rooms (Easy)
Non-overlapping Intervals (Medium)
Interval List Intersections (Medium)
Minimum Arrows to Burst Balloons (Medium)
Car Pooling (Sweep Line) (Medium)
My Calendar I (Medium)
Summary Ranges (Easy)
Remove Covered Intervals (Medium)
My Calendar II (Medium)
Data Stream as Disjoint Intervals (Hard)
Minimum Interval to Include Each Query (Hard)
My Calendar III (Hard)
Video Stitching (Medium)
Missing Ranges (Easy)
Meeting Scheduler (Medium)
Count Days Without Meetings (Medium)
Range Module (Hard)
Divide Intervals Into Minimum Number of Groups (Medium)
Find Right Interval (Medium)
Minimum Time Difference (Medium)
The Skyline Problem (Hard)
Employee Free Time (Hard)
Brightest Position on Street (Medium)
Remove Interval (Medium)
Points That Intersect With Cars (Easy)

Trie

Word Search II (Hard)
Implement a Trie (Prefix Tree) (Medium)
Design Add and Search Words (Wildcards) (Medium)
Search Suggestions (Autocomplete) (Medium)
Maximum XOR of Two Numbers (Medium)
Replace Words (Medium)
Longest Word in Dictionary (Medium)
Map Sum Pairs (Medium)
Design Search Autocomplete System (Hard)
Concatenated Words (Hard)
Stream of Characters (Hard)
Palindrome Pairs (Hard)
Prefix and Suffix Search (Hard)
Implement Magic Dictionary (Medium)
Short Encoding of Words (Medium)
Sum of Prefix Scores of Strings (Hard)
Design In-Memory File System (Hard)
Design File System (Medium)
Find the Length of the Longest Common Prefix (Medium)
Lexicographical Numbers (Medium)
Remove Sub-Folders from the Filesystem (Medium)
Words Within Two Edits of Dictionary (Medium)
Index Pairs of a String (Easy)
Count Prefix and Suffix Pairs (Easy)

Bit Manipulation

Single Number (XOR) (Easy)
Number of 1 Bits (Brian Kernighan) (Easy)
Counting Bits (Easy)
Power of Two (Easy)
Missing Number (Easy)
Set Mismatch (Duplicate and Missing) (Easy)
Sum of Two Integers Without + or - (Medium)
Partition to K Equal Sum Subsets (Bitmask DP) (Medium)
Add Binary (Easy)
Hamming Distance (Easy)
Single Number II (Medium)
Single Number III (Medium)
Bitwise AND of Numbers Range (Medium)
Total Hamming Distance (Medium)
Find the Difference (Easy)
Minimum Flips to Make a OR b Equal to c (Medium)
Gray Code (Medium)
Maximum Product of Word Lengths (Medium)
Divide Two Integers (Medium)
UTF-8 Validation (Medium)
Reverse Bits (Easy)
Number Complement (Easy)
Binary Watch (Easy)
Minimum Operations to Reduce an Integer to 0 (Medium)
Minimum Bit Flips to Convert Number (Easy)
Concatenation of Consecutive Binary Numbers (Medium)
Bitwise ORs of Subarrays (Medium)
Binary Gap (Easy)
Find Kth Bit in Nth Binary String (Medium)
XOR Queries of a Subarray (Medium)
Number of Steps to Reduce a Number to Zero (Easy)
Find The Original Array of Prefix Xor (Medium)

Math & Number Theory

Prime Check (Easy)
Count Primes (Sieve of Eratosthenes) (Medium)
Greatest Common Divisor of Strings (Easy)
Pow(x, n) — Fast Exponentiation (Medium)
Modular Exponentiation (Medium)
Binomial Coefficient nCr mod 10⁹+7 (Medium)
Permutation Sequence (k-th Permutation) (Hard)
Nth Magical Number (LCM + Binary Search) (Hard)
Reservoir Sampling (Medium)
Palindrome Number (Easy)
Reverse Integer (Medium)
Roman to Integer (Easy)
Integer to Roman (Medium)
String to Integer (atoi) (Medium)
Multiply Strings (Medium)
Excel Sheet Column Title (Easy)
Fraction to Recurring Decimal (Medium)
Integer to English Words (Hard)
Angle Between Hands of a Clock (Medium)
Plus One (Easy)
Add Strings (Easy)
Fizz Buzz (Easy)
Count and Say (Medium)
Bulb Switcher (Medium)
Valid Number (Hard)
Max Points on a Line (Hard)
Robot Bounded In Circle (Medium)
Sequential Digits (Medium)
Power of Three (Easy)
Ugly Number (Easy)
Add Digits (Easy)
Perfect Number (Easy)
Sum of Square Numbers (Medium)
Rotate Function (Medium)
Count Good Numbers (Medium)
Number of Digit One (Hard)
Compare Version Numbers (Medium)
Excel Sheet Column Number (Easy)
Nth Digit (Medium)
Factorial Trailing Zeroes (Medium)
Water and Jug Problem (Medium)
Nim Game (Easy)
The kth Factor of n (Medium)
Count Numbers with Unique Digits (Medium)
Rectangle Area (Medium)
Base 7 (Easy)
Find the Closest Palindrome (Hard)

Low-Level Design

Design a Parking Lot (Medium)
Design an Elevator System (Hard)
Design a Vending Machine (Medium)
Implement a Rate Limiter Class (Medium)
Design Snakes and Ladders (Easy)
Design the Snake Game (Medium)
Design Connect Four (Easy)
Design a Chess Game (Hard)
Design a Deck of Cards for Blackjack (Easy)
Design Tic-Tac-Toe (Easy)
Design Amazon Locker (Medium)
Design Splitwise (Medium)
Design an ATM (Medium)
Design a Library Management System (Easy)
Design a Meeting Room Scheduler (Medium)
Design a Ride-Hailing Service (Medium)
Design a Food Delivery Order Assignment System (Medium)
Design a Digital Wallet (Medium)
Design a Discount and Coupon Engine (Medium)
Design a Cross-Product Tagging System (Medium)
Design a Content Popularity Tracker (Medium)
Design a Movie Ticket Booking System (Medium)
Design an In-Memory Banking System (Medium)
Design an In-Memory Cloud File Storage (Medium)
Design a Music Player (Medium)
Design a Q&A Site like Stack Overflow (Medium)
Design an Online Auction (Medium)
Design a Text Editor with Undo and Redo (Medium)
Design a Spreadsheet with Formulas (Hard)
Design a Support Agent Rating System (Medium)
Design a Car Rental Booking System (Medium)
Design a Logging Framework (Medium)
Design an In-Memory Pub/Sub Message Broker (Medium)
Design a Task Scheduler (Hard)
Design a File Search Tool (Unix find) (Medium)
Design a Stock Exchange Order Book (Hard)
Design an HTTP Router (Medium)
Design a Circuit Breaker (Medium)
Design a Notification Service (Medium)
Design a Cache with Pluggable Eviction (Medium)
Design a Bounded Blocking Queue (Medium)
Design an In-Memory File System (Medium)

Behavioral

Tell me about yourself (Easy)
Tell me about a conflict with a coworker (Medium)
Tell me about a time you disagreed with your manager (Medium)
Tell me about a time you failed (Medium)
Walk me through your most impactful project (Medium)
Tell me about a time you worked with ambiguity (Medium)
Tell me about a time you had to meet a tight deadline (Easy)
Tell me about critical feedback you received (Easy)
Tell me about a time you helped someone grow (Medium)
Why do you want to work here? (Easy)
Why are you leaving your current role? (Easy)
What are you looking for in your next team? (Easy)
Where do you see yourself in five years? (Easy)
Tell me about a time you took ownership beyond your role (Medium)
Tell me about a problem you noticed that nobody else was addressing (Medium)
Tell me about a project you drove from idea to launch (Medium)
Tell me about working with a difficult stakeholder (Medium)
Tell me about a time you had to compromise (Easy)
Tell me about delivering a project across multiple teams (Hard)
Tell me about a time you led without formal authority (Medium)
Tell me about a time you convinced others to adopt your idea (Medium)
Tell me about a time you improved how your team works (Medium)
Tell me about working with an underperforming teammate (Hard)
Tell me about a decision you made with incomplete information (Medium)
Tell me about a difficult technical trade-off you made (Hard)
Tell me about a time you had to change direction mid-project (Medium)
How do you prioritize competing demands? (Easy)
Tell me about a time you had to cut scope (Medium)
Tell me about a mistake that affected others (Medium)
What is a weakness you're working on? (Easy)
Tell me about a production incident you handled (Medium)
Tell me about the hardest bug you've debugged (Medium)
Tell me about a time you had to learn something new quickly (Easy)
Tell me about a time you pushed back on a request (Medium)
Tell me about a time you made the case for paying down tech debt (Hard)
What questions do you have for me? (Easy)
Tell me about a time you went above and beyond for a customer (Medium)
Tell me about a time you dove deep to find the root cause (Hard)
Tell me about a time you took a calculated risk (Medium)
Tell me about a time you simplified something complex (Medium)
Tell me about a time you refused to compromise on quality (Hard)
Tell me about a time you did more with less (Medium)
Tell me about a time you had to earn the trust of a skeptical team (Medium)
Tell me about a time you proposed a bold vision (Hard)
Tell me about a time you delivered despite a major setback (Medium)
Tell me about a judgment call where others disagreed with you (Hard)
Tell me about something you learned outside your job that made you better at it (Easy)
Tell me about raising the bar when hiring or developing people (Hard)
Your team is split on a technical direction. What do you do? (Medium)
Tell me about a time you made sure every voice on your team was heard (Medium)
Tell me about a time you advocated for users (Medium)
Tell me about a time you shipped fast and iterated (Medium)
Tell me about a time you kept going on a problem that seemed stuck (Hard)
Tell me about creating structure in a chaotic situation (Medium)
Tell me about a time you changed your mind (Medium)
Tell me about a time you gave difficult feedback to a peer (Hard)
Tell me about a big decision you made without asking for permission (Hard)
What part of our culture would be hardest for you? (Medium)
Tell me about a time you argued for users over an easier option (Medium)
Tell me about a time you sweated the details (Medium)
Tell me about a time your values were tested at work (Hard)
Tell me about a time you balanced speed against safety (Hard)
Why do you want to work on AI? (Easy)
Tell me about a time you made someone feel they belonged (Easy)
Tell me about a time you stepped far outside your comfort zone (Medium)
Tell me about a time your first impression was wrong (Medium)
Tell me about a time you stood up for the customer (Medium)
Tell me about a time you challenged a more senior colleague (Hard)
Walk me through your life story (Medium)
Describe the hardest problem you've solved (Hard)
Tell me about solving a problem from first principles (Hard)
Teach me something you recently learned (Medium)
Why Bloomberg, and why financial technology? (Easy)
Tell me about collaborating closely with design or hardware teams (Medium)

AI-Assisted Coding

Extend an Unfamiliar Codebase with AI (Medium)
Debug a Failing Test Suite with AI (Medium)
Build a Small App from a Spec with AI (Hard)
Add Tests to an Untested Module with AI (Medium)
Refactor a Legacy Module with AI (Medium)
Fix a Slow Endpoint with AI (Medium)
Review an AI-Generated Pull Request (Medium)
Build a Multi-Level In-Memory Store with AI (Hard)
Integrate a Paginated, Rate-Limited API with AI (Medium)
Analyze Logs with a Script and AI (Medium)
Fix a Concurrency Bug with AI (Hard)
Ship a Feature Behind a Flag with a Data Migration (Medium)