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Top 50 Data Structures Interview Questions

The most frequently asked Data Structures questions across all roles and companies, ranked by real interview frequency. Updated daily.

50questions
~21htotal time
280companies covered
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1
RecursionStart here. 5 questions · ~125 min
Check Palindrome StringEasy
Practice
Recently asked

Use a two-pointer string scan to determine whether a string reads the same forward and backward.

RecursionStringsData StructuresDsv Air & SeaLucid MotorsAfterquery
Reverse a Linked ListEasy
Practice
Recently asked

Reverse a singly linked list iteratively and recursively while preserving every node and returning the new head.

Recursioncoding challengeLinked ListsNetsuiteMacquarie GroupAAppLogic Networks
Reverse a Linked ListEasy
Practice
Recently asked

Reverse a singly linked list in place using iterative pointer manipulation with O(n) time and O(1) extra space.

RecursionCodingLinked ListsLenovoSprinklrNNexturn
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2
Hash Tables6 questions · ~150 min
3
Data Structures11 questions · ~275 min
Cycle Detection in Linked ListEasy
Practice
Recently asked

Detect a cycle in a Capgemini Engineering linked-list model using Floyd's tortoise-and-hare algorithm in O(n) time and O(1) space.

Data StructuresCapgemini EngineeringRelativity SpaceIntuitive Surgical
Linked List ImplementationMedium
Practice
Recently asked

Implement a doubly linked list with indexed access, mutation, reversal, and constant-time end operations.

Data StructuresHHays TechnologyHaysinternational advanced analytics data
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4
coding challenge3 questions · ~75 min
In-Place Linked List ReversalEasy
Practice
Recently asked

Reverse a singly linked list in place using constant extra space and return its new head.

coding challengeLinked ListsData StructuresBBambooBoxEEmbitel Technologies‍Telesign
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5
Arrays4 questions · ~100 min
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6
Linked Lists3 questions · ~75 min
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7
More topics18 questions · ~450 min
Reverse Linked List ComplexityEasy
Practice

Reverse a singly linked list in place using pointer reassignment with O(n) time and O(1) extra space.

time complexityLinked ListsData StructuresSamsung ElectronicsADPOpen Systems Technologies
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