2116. Check if a Parentheses String Can Be Valid

class Solution:
    def canBeValid(self, s: str, locked: str) -> bool:
        n = len(s)
        if n & 1:
            return False
        x = 0
        for i in range(n):
            if s[i] == '(' or locked[i] == '0':
                x += 1
            elif x:
                x -= 1
            else:
                return False
        x = 0
        for i in range(n - 1, -1, -1):
            if s[i] == ')' or locked[i] == '0':
                x += 1
            elif x:
                x -= 1
            else:
                return False
        return True