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PhantomCodeAI
Features
Mock Interview
Dashboard
Jobs
Pricing
Resources
Help
Features
Mock Interview
Dashboard
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Help
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LeetCode Problems
Design
Design
Problems
94 Design LeetCode problems · Solve with AI-powered hints & step-by-step explanations.
146
LRU Cache
Medium
155
Min Stack
Medium
173
Binary Search Tree Iterator
Medium
208
Implement Trie (Prefix Tree)
Medium
211
Design Add and Search Words Data Structure
Medium
225
Implement Stack using Queues
Easy
232
Implement Queue using Stacks
Easy
284
Peeking Iterator
Medium
295
Find Median from Data Stream
Hard
297
Serialize and Deserialize Binary Tree
Hard
303
Range Sum Query - Immutable
Easy
304
Range Sum Query 2D - Immutable
Medium
307
Range Sum Query - Mutable
Medium
341
Flatten Nested List Iterator
Medium
352
Data Stream as Disjoint Intervals
Hard
355
Design Twitter
Medium
380
Insert Delete GetRandom O(1)
Medium
381
Insert Delete GetRandom O(1) - Duplicates allowed
Hard
384
Shuffle an Array
Medium
432
All O`one Data Structure
Hard
449
Serialize and Deserialize BST
Medium
460
LFU Cache
Hard
535
Encode and Decode TinyURL
Medium
622
Design Circular Queue
Medium
641
Design Circular Deque
Medium
676
Implement Magic Dictionary
Medium
677
Map Sum Pairs
Medium
703
Kth Largest Element in a Stream
Easy
705
Design HashSet
Easy
706
Design HashMap
Easy
707
Design Linked List
Medium
715
Range Module
Hard
729
My Calendar I
Medium
731
My Calendar II
Medium
732
My Calendar III
Hard
745
Prefix and Suffix Search
Hard
855
Exam Room
Medium
895
Maximum Frequency Stack
Hard
900
RLE Iterator
Medium
901
Online Stock Span
Medium
911
Online Election
Medium
919
Complete Binary Tree Inserter
Medium
933
Number of Recent Calls
Easy
981
Time Based Key-Value Store
Medium
1032
Stream of Characters
Hard
1146
Snapshot Array
Medium
1157
Online Majority Element In Subarray
Hard
1172
Dinner Plate Stacks
Hard
1206
Design Skiplist
Hard
1261
Find Elements in a Contaminated Binary Tree
Medium
1286
Iterator for Combination
Medium
1348
Tweet Counts Per Frequency
Medium
1352
Product of the Last K Numbers
Medium
1357
Apply Discount Every n Orders
Medium
1381
Design a Stack With Increment Operation
Medium
1396
Design Underground System
Medium
1472
Design Browser History
Medium
1476
Subrectangle Queries
Medium
1483
Kth Ancestor of a Tree Node
Hard
1600
Throne Inheritance
Medium
1603
Design Parking System
Easy
1622
Fancy Sequence
Hard
1656
Design an Ordered Stream
Easy
1670
Design Front Middle Back Queue
Medium
1797
Design Authentication Manager
Medium
1825
Finding MK Average
Hard
1845
Seat Reservation Manager
Medium
1865
Finding Pairs With a Certain Sum
Medium
1912
Design Movie Rental System
Hard
1993
Operations on Tree
Medium
2013
Detect Squares
Medium
2034
Stock Price Fluctuation
Medium
2043
Simple Bank System
Medium
2069
Walking Robot Simulation II
Medium
2080
Range Frequency Queries
Medium
2102
Sequentially Ordinal Rank Tracker
Hard
2166
Design Bitset
Medium
2227
Encrypt and Decrypt Strings
Hard
2241
Design an ATM Machine
Medium
2276
Count Integers in Intervals
Hard
2286
Booking Concert Tickets in Groups
Hard
2296
Design a Text Editor
Hard
2336
Smallest Number in Infinite Set
Medium
2349
Design a Number Container System
Medium
2353
Design a Food Rating System
Medium
2424
Longest Uploaded Prefix
Medium
2502
Design Memory Allocator
Medium
2526
Find Consecutive Integers from a Data Stream
Medium
2642
Design Graph With Shortest Path Calculator
Hard
2671
Frequency Tracker
Medium
3242
Design Neighbor Sum Service
Easy
3408
Design Task Manager
Medium
3484
Design Spreadsheet
Medium
3508
Implement Router
Medium
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