1249. Minimum Remove to Make Valid Parentheses (Medium) - TengnanYao/daily_leetcode GitHub Wiki

class Solution(object):
    def minRemoveToMakeValid(self, s):
        """
        :type s: str
        :rtype: str
        """
        stack, result = [], list(s)
        for i, c in enumerate(s):
            if c == "(":
                stack.append(i)
            elif c == ")":
                if stack:
                    stack.pop()
                else:
                    result[i] = ""
        for i in stack:
            result[i] = ""
        return "".join(result)