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Problem
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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:
s.lengthscontains only lowercase English letters.
Examples
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Tap here to switch tabs
Problem
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:
s.lengthscontains only lowercase English letters.
Examples
Understand the problem
Figure it out!
Try it yourself
Unlock AI-Powered LearningUpgrade to smarter learning with instant explanations of Ask Agent, Personalized Interview Prep, Real-World Projects, 3 AI Mock Interviews per month, and Personalized Paths