Top 50 String Coding Problems for Interviews
Last Updated :
19 Feb, 2025
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String-related problems often assess a candidate’s understanding of concepts like pattern matching, manipulation, and efficient algorithm design. Here is the collection of the Top 50 list of frequently asked interview questions on Strings. Problems in this Article are divided into three Levels so that readers can practice according to the difficulty level step by step.
Easy Problems
- Palindrome Check
- Reverse a String
- Reverse words in a given string
- Check for Rotation
- First Non Repeating
- Longest Common Prefix
- Roman Number to Integer
- Integer to Roman
- Closest Strings
- Divisible by 7
- Encrypt the String – II
- Equal point in a string of brackets
- Isomorphic Strings
- Check if two strings are k-anagrams or not
- Panagram Checking
- Minimum Deletions
- Number of Distinct Subsequences
Medium Problems
- Implement Atoi
- License Key Formatting
- Find the largest word in dictionary
- Equal 0,1, and 2
- Find and replace in String
- Add Binary Strings
- Sum of two large numbers
- Multiply two strings
- Look and say Pattern
- Minimum times A has to be repeated to make B a Substring
- Excel Sheet – I
- Form a Palindrome
- Find the N-th character
- Next higher palindromic number using the same set of digits
- Length of longest prefix suffix
- Longest K unique characters substring
- Smallest window in string containing all characters
- Longest Palindromic Subsequence
- Longest substring without repeating characters
- Substrings of length k with k-1 distinct elements
- Count number of substrings
- Interleaved Strings
- Print Anagrams together
- Rank the permutation
- A Special Keyboard
Hard Problems
- Restrictive Candy Crush
- Edit Distance
- Search Pattern (KMP-Algorithm)
- Search Pattern (Rabin-Karp Algorithm)
- Shortest Common Supersequence
- Number of words with K maximum distinct vowels
- Longest substring to form a Palindrome
- Longest Valid Parenthesis
- Distinct Palindromic Substrings
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