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Top 50 Strings Interview Questions

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

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1
StringsStart here. 6 questions · ~150 min
Reverse a String in PythonEasy
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Recently asked

Reverse a string in Python using character traversal and return the reversed result.

StringsfunctionspythonCNAAct DigitalLos Alamos National Laboratory
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2
Hash Tables23 questions · ~575 min
Two Sum with TargetEasy
Practice
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Use a hash map to find two array elements that sum to a target in O(n) time.

Hash TablesArraysStringsiCapitalPaycomBlend360
Longest Substring Without RepeatsMedium
Practice
Recently asked

Find the longest substring with all unique characters using a sliding window.

Hash TablesStringsTwo PointersDeepInstinctTaboolaEDF Renewables
First Non-Repeating CharacterEasy
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Recently asked

Find the first non-repeating character in a string using frequency counting and a second pass in O(n) time.

Hash TablesStringsSearchingCloudsekBrightside HealthMcAfee
Longest Unique Substring in EnoMedium
Practice
Recently asked

Use a sliding window and hash map to find the longest substring without repeated characters in a string.

Hash TablesStringsTwo PointersInsight GlobalO'Reilly MediaAviso
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3
Recursion11 questions · ~275 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
Palindrome FunctionEasy
Practice
Recently asked

Use two pointers to determine whether a City National Bank reference label reads identically forward and backward.

RecursionStringsTwo PointersTaboolaiHerbSharpSpring
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4
Math3 questions · ~75 min
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5
More topics7 questions · ~175 min
Longest Common Prefix in StringsEasy
Practice
Recently asked

Find the longest shared starting substring across an array of strings using prefix shrinking.

ArraysStringsGEICOCloudscouts Software SolutionsPing Identity
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