String Interview Questions

Hash Table String Dynamic Programming Counting Enumeration

Rank

#3638HardFrequency: 100%

Minimum Operations to Make Character Frequencies Equal

Asked at TikTok

Rank

#3613MediumFrequency: 100%

Maximize Amount After Two Days of Conversions

Array String Depth-First Search Breadth-First Search Graph

Rank

#49MediumFrequency: 100%

Group Anagrams

Asked at Oracle

Array Hash Table String Sorting

Rank

#71MediumFrequency: 100%

Simplify Path

Asked at Oracle

Rank

#1423MediumFrequency: 100%

Maximum Number of Occurrences of a Substring

Asked at Salesforce

Rank

#227MediumFrequency: 96%

Basic Calculator II

Math String Stack

Rank

#680EasyFrequency: 95%

Valid Palindrome II

Two Pointers String Greedy

Rank

#647MediumFrequency: 88%

Palindromic Substrings

Asked at Salesforce

Two Pointers String Dynamic Programming

Rank

#408EasyFrequency: 87%

Valid Word Abbreviation

#10

Rank

#125EasyFrequency: 87%

Valid Palindrome

Asked at Oracle

#11

Rank

#3MediumFrequency: 84%

Longest Substring Without Repeating Characters

#12

Rank

#8MediumFrequency: 84%

String to Integer (atoi)

Asked at Databricks

#13

Rank

#752MediumFrequency: 84%

IP to CIDR

Asked at Databricks

String Bit Manipulation

#14

Rank

#1894EasyFrequency: 80%

Merge Strings Alternately

#15

Rank

#14EasyFrequency: 80%

Longest Common Prefix

Asked at Apple

String Trie

#16

Rank

#269HardFrequency: 79%

Alien Dictionary

Array String Depth-First Search Breadth-First Search Graph Topological Sort

#17

Rank

#224HardFrequency: 73%

Basic Calculator

Asked at DoorDash

Math String Stack Recursion

#18

Rank

#1397MediumFrequency: 73%

Search Suggestions System

Asked at DoorDash

Array String Binary Search Trie Sorting Heap (Priority Queue)

#19

Rank

#1915EasyFrequency: 73%

Check if One String Swap Can Make Strings Equal

Asked at DoorDash

Hash Table String Counting

#20

Rank

#778MediumFrequency: 72%

Reorganize String

Hash Table String Greedy Sorting Heap (Priority Queue)Counting

#21

Rank

#139MediumFrequency: 72%

Word Break

Asked at TikTok

Array Hash Table String Dynamic Programming Trie Memoization

#22

Rank

#20EasyFrequency: 71%

Valid Parentheses

Asked at Apple

Hash Table String Breadth-First Search

#23

Rank

#127HardFrequency: 71%

Word Ladder

Asked at Apple

#24

Rank

#65HardFrequency: 69%

Valid Number

#25

Rank

#957MediumFrequency: 66%

Minimum Add to Make Parentheses Valid

String Stack Greedy

#26

Rank

#79MediumFrequency: 63%

Word Search

Array String Backtracking Matrix

#27

Rank

#399MediumFrequency: 63%

Evaluate Division

Array String Depth-First Search Breadth-First Search Union Find Graph Shortest Path

#28

Rank

#244MediumFrequency: 63%

Shortest Word Distance II

Asked at LinkedIn

Array Hash Table Two Pointers String Design

#29

Rank

#721MediumFrequency: 62%

Accounts Merge

Array Hash Table String Depth-First Search Breadth-First Search Union Find Sorting

#30

Rank

#1178HardFrequency: 62%

Valid Palindrome III

String Dynamic Programming

#31

Rank

#415EasyFrequency: 62%

Add Strings

Asked at TikTok

Math String Simulation

#32

Rank

#2414MediumFrequency: 60%

Move Pieces to Obtain a String

#33

Rank

#3018MediumFrequency: 60%

Make String a Subsequence Using Cyclic Increments

#34

Rank

#76HardFrequency: 60%

Minimum Window Substring

#35

Rank

#807MediumFrequency: 60%

Custom Sort String

Hash Table String Sorting

#36

Rank

#6MediumFrequency: 56%

Zigzag Conversion

#37

Rank

#17MediumFrequency: 56%

Letter Combinations of a Phone Number

Hash Table String Backtracking

#38

Rank

#5MediumFrequency: 55%

Longest Palindromic Substring

Two Pointers String Dynamic Programming

#39

Rank

#12MediumFrequency: 55%

Integer to Roman

Hash Table Math String

#40

Rank

#205EasyFrequency: 55%

Isomorphic Strings

Hash Table String

#41

Rank

#273HardFrequency: 55%

Integer to English Words

Math String Recursion

#42

Rank

#291MediumFrequency: 55%

Word Pattern II

Hash Table String Backtracking

#43

Rank

#567MediumFrequency: 55%

Permutation in String

Hash Table Two Pointers String Sliding Window

#44

Rank

#1128EasyFrequency: 55%

Remove All Adjacent Duplicates In String

#45

Rank

#1566EasyFrequency: 55%

Check If a Word Occurs As a Prefix of Any Word in a Sentence

Two Pointers String String Matching

#46

Rank

#22MediumFrequency: 53%

Generate Parentheses

String Dynamic Programming Backtracking

#47

Rank

#2300MediumFrequency: 53%

Construct String With Repeat Limit

Hash Table String Greedy Heap (Priority Queue)Counting

#48

Rank

#387EasyFrequency: 51%

First Unique Character in a String

Hash Table String Queue Counting

#49

Rank

#28EasyFrequency: 48%

Find the Index of the First Occurrence in a String

Two Pointers String String Matching

#50

Rank

#2232MediumFrequency: 48%

Adding Spaces to a String

Array Two Pointers String Simulation

#51

Rank

#10HardFrequency: 45%

Regular Expression Matching

String Dynamic Programming Recursion

#52

Rank

#126HardFrequency: 45%

Word Ladder II

Hash Table String Backtracking Breadth-First Search

#53

Rank

#151MediumFrequency: 45%

Reverse Words in a String

#54

Rank

#3410HardFrequency: 45%

Find Longest Self-Contained Substring

Hash Table String Binary Search Prefix Sum

#55

Rank

#249MediumFrequency: 43%

Group Shifted Strings

Array Hash Table String

#56

Rank

#851EasyFrequency: 43%

Goat Latin

#57

Rank

#13EasyFrequency: 42%

Roman to Integer

Hash Table Math String

#58

Rank

#179MediumFrequency: 42%

Largest Number

Array String Greedy Sorting

#59

Rank

#383EasyFrequency: 42%

Ransom Note

Hash Table String Counting

#60

Rank

#394MediumFrequency: 42%

Decode String

String Stack Recursion

#61

Rank

#424MediumFrequency: 42%

Longest Repeating Character Replacement

#62

Rank

#282HardFrequency: 37%

Expression Add Operators

Math String Backtracking

#63

Rank

#58EasyFrequency: 33%

Length of Last Word