#2982
Find Longest Special Substring That Occurs Thrice II
expert · 1025 · lc medium +32 · verified · 39.1% accepted · 407 likes · top 18%
Description
You are given a string s consisting of lowercase English letters.
A string is special if it is composed of only one distinct character. For example, "ddd", "zz", and "f" are special, while "abc" is not.
Return the length of the longest special substring of s that occurs at least three times, or -1 if no such substring exists.
A substring is a contiguous non-empty sequence of characters within a string.
Example 1:
Input: s = "aaaa"
Output: 2
Explanation: The longest special substring which occurs thrice is "aa": substrings "aaaa", "aaaa", and "aaaa".
It can be shown that the maximum length achievable is 2.
Example 2:
Input: s = "abcdef"
Output: -1
Explanation: There exists no special substring which occurs at least thrice. Hence return -1.
Example 3:
Input: s = "abcaba"
Output: 1
Explanation: The longest special substring which occurs thrice is "a": substrings "abcaba", "abcaba", and "abcaba".
It can be shown that the maximum length achievable is 1.
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