Watch 10 video solutions for Longest Happy Prefix, a hard level problem involving String, Rolling Hash, String Matching. This walkthrough by Ashish Pratap Singh has 1,002,177 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
A string is called a happy prefix if is a non-empty prefix which is also a suffix (excluding itself).
Given a string s, return the longest happy prefix of s. Return an empty string "" if no such prefix exists.
Example 1:
Input: s = "level"
Output: "l"
Explanation: s contains 4 prefix excluding itself ("l", "le", "lev", "leve"), and suffix ("l", "el", "vel", "evel"). The largest prefix which is also suffix is given by "l".
Example 2:
Input: s = "ababab" Output: "abab" Explanation: "abab" is the largest prefix which is also suffix. They can overlap in the original string.
Constraints:
1 <= s.length <= 105s contains only lowercase English letters.