Strings
Master string manipulation with pattern matching, parsing, and advanced string algorithms.
Showing 20 of 20 questions
Easy: 8 Medium: 7 Hard: 5
| Question | Difficulty |
|---|---|
Check if String is Palindrome Determine if a string reads the same forwards and backwards, ignoring case and non-alphanumeric characters. | Easy |
Check if String is Rotation of Another Determine if one string is a rotation of another string by checking if it can be formed by rotating the characters. | Easy |
First Unique Character in String Find the first non-repeating character in a string and return its index. | Easy |
Implement strStr (Find Substring) Find the first occurrence of a substring in a string, similar to strstr() function. | Easy |
Longest Common Prefix Find the longest common prefix string amongst an array of strings. | Easy |
Reverse String Reverse a string in-place using O(1) extra memory. | Easy |
Valid Anagram Determine if two strings are anagrams of each other | Easy |
Valid Parentheses Check if a string containing only parentheses is valid. | Easy |
Count and Say Generate the nth term of the count-and-say sequence. | Medium |
Generate Permutations Generate all possible permutations of a given string. | Medium |
Group Anagrams Group strings that are anagrams of each other together. | Medium |
Longest Palindromic Substring Find the longest palindromic substring in a given string | Medium |
Longest Substring Without Repeating Characters Find the length of the longest substring without repeating characters | Medium |
String Compression Compress a string by replacing consecutive characters with character and count. | Medium |
Word Break Determine if a string can be segmented into space-separated words from a dictionary. | Medium |
Edit Distance (Levenshtein Distance) Find the minimum number of operations (insert, delete, replace) required to transform one string into another. | Hard |
Longest Repeated Substring Find the longest substring that appears at least twice in a string | Hard |
Minimum Window Substring Find the minimum window substring that contains all characters of another string | Hard |
Regular Expression Matching Implement regular expression matching with support for '.' and '*' | Hard |
Smallest Substring with All Characters Find the smallest substring that contains all characters of a given pattern | Hard |