class Solution(object):
    def isValid(self, s):
        """
        :type s: str
        :rtype: bool
        """
        list1=[]
        tuple1=('{}','()','[]')
        for i in s:
            if i in ('{','[','('):
                list1.append(i)
            if i in ('}',']',')'):
                if list1==[]:
                    return False
                a=list1.pop()
                if a+i in tuple1:
                    pass
                else:
                    return False
        if list1==[]:
            return True
        else:
            return False

重点：

1. 使用数组作为栈，append(i)&pop()
2. 有两处需要判断list是否为空