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Updated weekly · Last refresh Sep 12

Top 50 Algorithms Interview Questions

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

50questions
~21htotal time
334companies covered
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1
RecursionStart here. 7 questions · ~175 min
Check Palindrome StringEasy
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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
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Recently asked

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

Recursioncoding challengeLinked ListsNetsuiteMacquarie GroupAAppLogic Networks
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2
Linked Lists4 questions · ~100 min
Reverse Linked List In-PlaceEasy
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Reverse a singly linked list in place by rewiring next pointers in one pass.

Linked ListsAlgorithmsGeneral AtomicsKKotakKotak Mahindra Bank
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3
string manipulation3 questions · ~75 min
Reverse Words in a StringEasy
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Reverse the order of words in a report string while preserving each word and normalizing whitespace.

string manipulationAlgorithmsLeidosHHelmerich & PayneTencent
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4
coding challenge5 questions · ~125 min
Reverse Words in SentenceMedium
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Reverse each word's characters while preserving the sentence's word order using a linear scan.

coding challengeBasic AlgorithmsStringsAmerican AirlinesPocket FmBBestPeers Infosystem
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5
Arrays4 questions · ~100 min
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6
Basic Algorithms4 questions · ~100 min
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7
More topics23 questions · ~575 min
Two Sum Coding ProblemEasy
Practice
Recently asked

Find two array values that sum to a target using a hash map in O(n) time.

leetcodeAlgorithmsBooz Allen HamiltonVanguardAscendion
Shortest Path in Weighted GraphHard
Practice
Recently asked

Use Dijkstra’s algorithm with a priority queue to find the shortest path in a weighted graph with non-negative edges.

shortest pathAlgorithmsGraphsSuccessKPITikTok ShopYelp
Merge Overlapping Time IntervalsMedium
Practice
Recently asked

Merge overlapping intervals by sorting on start time, then scanning once to combine intersecting ranges.

time complexityAlgorithmsperformance analysisDatadogWurlFuku
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