Top String Coding Interview Questions

Strings are an integral part of coding interviews for placements. We have created a guide featuring top-string interview questions to strengthen the foundation of string and data structures to bring you a step closer to your dream job.

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Problem Title

Difficulty

Avg Time to solve

Attempted

Palindromic Substrings

68

Moderate

20 mins

1166

Edit Distance

62

Moderate

30 mins

13171

Decode String

22

Easy

15 mins

341

Reverse Words In A String

126

Easy

10 mins

9261

Wildcard Pattern Matching

118

Hard

50 mins

12618

Longest Substring Without Repeating Characters

38

Moderate

20 mins

1850

Longest Palindromic Substring

55

Easy

20 mins

3896

Valid Parentheses

98

Easy

10 mins

18640

Palindrome Partitioning

31

Moderate

25 mins

2843

Longest Palindromic Subsequence

25

Hard

45 mins

3911

Palindrome Partitioning ll

29

Hard

40 mins

6118

Find All Anagrams in a String

9

Easy

15 mins

489

Implement strStr()

2

Moderate

25 mins

464

Roman Numeral To Integer

25

Easy

15 mins

2367

Generate Parentheses

10

Easy

10 mins

925

Multiply Strings

36

Moderate

35 mins

2089

First unique character in a string

0

Moderate

15 mins

331

Letter Combinations of a Phone Number

10

Moderate

35 mins

1515

Minimum insertions to make a string palindrome

2

Moderate

30 mins

5627

Group Anagrams Together

2

Moderate

-

291

Restore IP Addresses

18

Moderate

15 mins

719

Compare Version Numbers

30

Easy

10 mins

2935

Longest Common Subsequence

17

Moderate

-

2838

Longest Valid Parentheses

9

Moderate

10 mins

438

Justify Text

12

Hard

35 mins

301

Palindromic Substrings

Moderate

68 upvotes

Edit Distance

Moderate

62 upvotes

Decode String

Easy

22 upvotes

Reverse Words In A String

Easy

126 upvotes

Wildcard Pattern Matching

Hard

118 upvotes

Longest Substring Without Repeating Characters

Moderate

38 upvotes

Longest Palindromic Substring

Easy

55 upvotes

Valid Parentheses

Easy

98 upvotes

Palindrome Partitioning

Moderate

31 upvotes

Longest Palindromic Subsequence

Hard

25 upvotes

Palindrome Partitioning ll

Hard

29 upvotes

Find All Anagrams in a String

Easy

9 upvotes

Implement strStr()

Moderate

2 upvotes

Roman Numeral To Integer

Easy

25 upvotes

Generate Parentheses

Easy

10 upvotes

Multiply Strings

Moderate

36 upvotes

First unique character in a string

Moderate

0 upvotes

Letter Combinations of a Phone Number

Moderate

10 upvotes

Minimum insertions to make a string palindrome

Moderate

2 upvotes

Group Anagrams Together

Moderate

2 upvotes

Restore IP Addresses

Moderate

18 upvotes

Compare Version Numbers

Easy

30 upvotes

Longest Common Subsequence

Moderate

17 upvotes

Longest Valid Parentheses

Moderate

9 upvotes

Justify Text

Hard

12 upvotes

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