Solution: Find Longest Special Substring That Occurs Thrice I

Statement

Given a string s, a substring is called special if it is made up of only one repeated character.

Return the maximum possible length of a special substring that appears in s at least three times. If no special substring occurs at least three times, return -1.

Note: Occurrences are counted by substring positions in s, and they may overlap.

Constraints:

• $3 \leq$ s.length $\le 50$ ...