【LeetCode】20. 有效的括号 python实现

题目描述

解题思路

构造一个栈，利用栈的先进后出的特性进行操作

python 代码

class Solution:
    def isValid(self, s: str) -> bool:
        a = []
        for i in s:
            if i == "(" or i == "{" or i == "[":
                a.append(i)
            elif i == ")" or i == "}" or i == "]":
                a.append(i)
                if len(a) == 1:
                    return False
                b = a[-2] + a[-1]
                if b == "()" or b == "{}" or b == "[]":
                    for i in range(2):
                        a.pop(-1)
        if a == []:
            return True
        else:
            return False

if __name__ == '__main__':
    s = Solution()
    res = s.isValid("(){}[]")
    print(res)