432. Longest happy prefix
Given a string s, return the longest happy prefix of s. A happy prefix is a string that is both a proper prefix and a proper suffix.
If no such prefix exists, return an empty string "".
Example 1:
Input: s = "ababab"
Output: "abab"
Explanation: "abab" is the longest prefix which is also suffix. They can overlap in the original string.
Example 2:
Input: s = "aaaa"
Output: "aaa"
Explanation: "aaa" is the longest prefix which is also a suffix in the string "aaaa".
Now Your Turn!
Pick the correct output for the given inputInput: s = "abc"
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Constraints:
- 1 <= s.length <= 104