Hard2026-09-20
Design a Chat Application like ChatGPT
UberSDE-2 (Backend)Onsite (HLD)
System DesignStreamingDatabase Design+1
Daily practice
Questions
Unique DSA problems from real interviews. No solutions — think through them yourself and build genuine problem-solving intuition.
61 questions
Medium2026-09-19
First Unique Number in a Stream
UberSDE-2 (Backend)Business Phone Screen (DSA)
DesignHashMapQueue+1
Medium2026-09-17
Design a Hit Counter (with Per-Element Counts)
UberSDE-2 (Backend)Onsite (DSA)
DesignHashMapQueue
Medium2026-09-15
Coin Game — Pick from Either Corner (Optimal Play)
TekionStaff Software EngineerR1 (Technical Screening)
Dynamic ProgrammingGame TheoryIntervals
Easy2026-09-14
100 Lockers — The Toggle Problem
TekionStaff Software EngineerR1 (Technical Screening)
MathNumber Theory
Medium2026-09-13
House Robber II — Circular Arrangement
AmazonSDE-1Onsite Round 1
Dynamic ProgrammingArrays
Hard2026-09-12
Design a Rate Limiter (System Design)
InfoEdgeSoftware EngineerRound 3 (System Design)
System DesignRate LimitingRedis+1
Medium2026-09-11
Design a Browser Tab Handler
InfoEdgeSoftware EngineerRound 3 (Design Coding)
DesignHashMapDoubly Linked List+1
Medium2026-09-10
Second Rightmost Node in a Binary Tree
InfoEdgeSoftware EngineerRound 4 (DSA)
Binary TreeBFSLevel Order Traversal
Medium2026-09-09
Search in Rotated Sorted Array
InfoEdgeSoftware EngineerRound 2 (Technical)
Binary SearchArrays
Medium2026-09-08
Design an LRU Cache
InfoEdgeSoftware EngineerRound 2 (Technical)
DesignHashMapDoubly Linked List
Easy2026-09-08
Rotate Array by K Steps
RakutenSDE (Java)Round 2 (DSA)
ArraysTwo PointersIn-Place
Medium2026-09-07
Number of Islands (Making an Island)
InfoEdgeSoftware EngineerRound 2 (Technical)
GraphBFSDFS+2
Medium2026-09-06
Minimum Cost Path in Grid with Cell Flipping
AmazonSDE-1Onsite Round 1
GraphBFSDijkstra+2
Medium2026-09-05
Design Device with Composable Capabilities (LLD)
AmazonSDE-1Onsite Round 2 (LLD)
LLDOOPInterface Design+1
Medium2026-09-04
Design a Bus Booking System (like RedBus)
RakutenSDE (Java)Round 2 (HLD)
System DesignConcurrencyDatabase Design
Medium2026-09-03
Design a Max Stack
MicrosoftL62 / Senior SDERound 4 (DSA)
StackDesignHeap
Medium2026-09-02
Heaters — Minimum Radius to Warm All Houses
MicrosoftL62 / Senior SDERound 1 (DSA)
Binary SearchSortingTwo Pointers
Hard2026-09-01
Design JIRA — Handling Concurrent Edits to the Same Ticket
MicrosoftL62 / Senior SDERound 2 (System Design)
System DesignConcurrencyOptimistic Locking+1
Hard2026-08-31
Design Google Docs — Real-Time Collaborative Editing
MicrosoftL62 / Senior SDERound 3 (High-Level Design)
System DesignOTCRDT+2
Easy2026-08-30
Add Two Large Numbers Represented as Strings
MicrosoftL62 / Senior SDERound 1 (DSA)
StringsMathSimulation
Hard2026-08-29
Design a Premium Cab Hailing Service (LLD)
UberSDE-II (L4)Round 3 (LLD)
LLDOOPMultithreading+1
Medium2026-08-28
Schedule Maximum Rakhi Celebrations
Google/Amazon/MicrosoftSDE-1 / SDE-2Onsite (Coding)
GreedySortingIntervals
Hard2026-08-27
Design a Stock Price Change Alert System
UberSDE-II (L4)Round 5 (System Design)
System DesignPush vs PullStreaming+1
Hard2026-08-26
Find Median from a Data Stream
UberSDE-II (L4)Round 2 (DSA)
HeapTwo HeapsDesign+1
Hard2026-08-25
Robot Path in Grid with Charging Stations (Multi-Priority Optimization)
UberSDE-II (L4)Round 1 (Screening)
GraphDijkstraBFS+1
Hard2026-08-24
Design Top-N Leaderboard with Rolling Time Windows
LinkedInSenior SDERound 5 (System Design)
System DesignRedisStreaming+1
Medium2026-08-24
Friend Suggestions Based on Mutual Connections
LinkedInSenior SDERound 4 (Coding with AI)
GraphBFSHashMap+1
Medium2026-08-24
Max Consecutive Ones III — With Circular Array Follow-up
LinkedInSenior SDERound 3 (Coding)
Sliding WindowArraysTwo Pointers
Hard2026-08-23
Design a Large-Scale Payment Processing Platform
SalesforceMTSRound 3 (System Design)
System DesignDistributed SystemsDatabase Design+1
Medium2026-08-23
Find All Anagrams of a Pattern in a String
SalesforceMTSRound 2 (DSA)
Sliding WindowHashMapStrings
Medium2026-08-23
Convert Sorted Doubly Linked List to Balanced BST (In-Place)
SalesforceMTSRound 1 (DSA)
Linked ListBinary TreeRecursion+1
Hard2026-08-23
Top K Frequent Numbers from a Continuous Stream
SalesforceMTSRound 1 (DSA)
HeapHashMapDesign+1
Medium2026-08-22
Multi-Source BFS in a Complex Scenario
GoogleSWE III (L5)Onsite Round 4
BFSGraphGrid+1
Medium2026-08-14
Implement Advanced Debounce with Leading Edge and Cancel
Flipkart/RazorpaySenior SDE (Frontend)Round 2 (JavaScript Deep Dive)
JavaScriptClosuresTimers+1
Hard2026-08-13
Shortest Subarray with Sum at Least K (with Negatives)
Google/Goldman SachsSDE-2 / AssociateOnsite (Coding)
Prefix SumDequeMonotonic Queue+1
Hard2026-08-12
Design and Implement a Distributed Job Scheduler
DigitalOceanSenior Software EngineerRound 1 (Coding + Deploy)
System DesignDistributed SystemsQueue+1
Hard2026-08-10
Design Microsoft Word — LLD with Undo/Redo
AdobeMTS-2 (C++)Round 3 (LLD)
LLDDesign PatternsOOP+1
Medium2026-08-09
Implement Basic Arithmetic Without Inbuilt Operators
AmazonSDE-2DSA Round
Bit ManipulationMathRecursion
Medium2026-08-09
Asteroid Collisions
AmazonSDE-2Bar Raiser
StackArraysSimulation
Medium2026-08-09
Implement Browser History Navigation
AmazonSDE-2DSA Round
DesignStackDoubly Linked List
Hard2026-08-09
Design an Auction Platform — Real-time Bidding System
AmazonSDE-2System Design
System DesignDatabase DesignCaching+1
Hard2026-08-08
Maximum of Every Sliding Window of Size K
Google/Amazon/MicrosoftSDE-2 / Senior SDEOnsite (Coding)
Sliding WindowDequeMonotonic Queue+1
Hard2026-08-04
Basic Calculator with OOP Extension
AmazonSDE-2Round 2 (Coding + Design)
StackParsingOOP+1
Hard2026-08-04
Data Migration Lag Verifier — Alert on Replication Delay
MongoDBSWE-3Round 3 (Real-world Problem)
System DesignQueueSliding Window+1
Medium2026-08-04
Find Distance Between Two Nodes in a Binary Tree
AmazonSDE-2Round 1 (DSA)
Binary TreeLCADFS+1
Medium2026-08-04
Group Buddy Strings by Cyclic Distance
GoogleL4 Software EngineerPhone Screen
StringsHashMapGrouping+1
Medium2026-08-04
Rotten Oranges — Multi-source BFS on Grid
AmazonSDE-2Bar Raiser
BFSGraphGrid+1
Hard2026-08-04
Design a Stack with O(1) Push, Pop, GetMiddle, and GetTop
AmazonSDE-2Round 1 (Design + DSA)
StackDesignDoubly Linked List+1
Medium2026-08-04
Design a Versioned Datastore with PUT and GET
MongoDBSWE-3Round 1 (Coding)
Binary SearchHashMapDesign+1
Hard2026-08-03
DP with Binary Search Optimization
GoogleSWE II (Early Careers)Technical Round 3
Dynamic ProgrammingBinary SearchOptimization
Hard2026-08-03
Modified Union-Find with Weighted Graph Components
GoogleSWE II (Early Careers)Technical Round 2
GraphDisjoint Set UnionUnion-Find
Medium2026-08-03
Trie + HashMap Based String Pattern Matching
GoogleSWE II (Early Careers)Technical Round 1
TrieHashMapStrings
Easy2026-08-01
Design a Tooltip Using Only HTML/CSS — No JavaScript
FreshworksSenior SDE (Fullstack)Round 2 (Frontend)
CSSHTMLUI Design
Medium2026-08-01
Implement Array.prototype.myFlat(depth)
FreshworksSenior SDE (Fullstack)Round 2 (Frontend)
JavaScriptRecursionPrototype
Medium2026-08-01
Rate Limiter — Count Dropped Requests
OracleSenior SDEOnsite (Stage 6)
Sliding WindowTwo PointersDesign
Medium2026-08-01
Stock Span Problem — All Three Variants
FreshworksSenior SDE (Fullstack)Round 1 (DSA)
StackMonotonic StackArrays
Medium2026-07-30
Remove Duplicates from Sorted Array — Allow at Most K
OracleSenior SDEOnsite (Stage 3)
ArrayTwo PointersIn-Place
Easy2026-07-30
Run-Length Encoding with Consecutive Count
OracleSenior SDEOnsite (Stage 3)
StringsTwo PointersEncoding
Medium2026-07-28
Bottom View of a Binary Tree
OracleSenior SDEOnsite (Stage 1)
Binary TreeBFSHashMap+1
Hard2026-07-28
Design a Remote Browser Isolation System
OracleSenior SDEOnsite (Stage 2 — System Design)
System DesignSecurityStreaming+1