1750. Minimum Length of String After Deleting Similar Ends.py

class Solution:
    def minimumLength(self, s: str) -> int:
        l, r = 0, len(s) - 1
        while l < r and s[l] == s[r]:
            ch = s[l]
            while l <= r and s[l] == ch:
                l += 1
            while l <= r and s[r] == ch:
                r -= 1
        return  r - l + 1