q20_Valid_Parentheses.py

class Solution:
    def isValid(self, s):
        """
        :type s: str
        :rtype: bool
        """
        stack = []
        dict = {"]": "[", "}": "{", ")": "("}
        for char in s:
            if char in dict.values():
                stack.append(char)
            elif char in dict.keys():
                if stack == [] or dict[char] != stack.pop():
                    return False
        return stack == []

s=Solution()
print(s.isValid("([])"))