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Problem: Longest Happy Prefix

hard
40 min
Explore how to identify the longest happy prefix in a string, a substring appearing at both the start and end but not the whole string. This lesson teaches you to apply hash map concepts to solve this problem efficiently, preparing you to recognize and implement similar patterns in coding interviews.

Statement

Given a string, s, find the longest happy prefix. If no such prefix exists, return an empty string "".

Note: A happy prefix of a string is a non-empty substring at the beginning that also appears at the end (but not the entire string itself).

Constraints:

  • 1<=1 <= s.length <=105<= 10^5

  • s contains only lowercase English letters.

Tap here to switch tabs
Problem
Ask
Submissions

Problem: Longest Happy Prefix

hard
40 min
Explore how to identify the longest happy prefix in a string, a substring appearing at both the start and end but not the whole string. This lesson teaches you to apply hash map concepts to solve this problem efficiently, preparing you to recognize and implement similar patterns in coding interviews.

Statement

Given a string, s, find the longest happy prefix. If no such prefix exists, return an empty string "".

Note: A happy prefix of a string is a non-empty substring at the beginning that also appears at the end (but not the entire string itself).

Constraints:

  • 1<=1 <= s.length <=105<= 10^5

  • s contains only lowercase English letters.