DAY9：leetcode #20 Valid Parentheses

路人甲wttttt

于 2016-07-22 16:15:17 发布

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分类专栏：算法文章标签： leetcode python

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本文介绍了一种使用Python实现的有效算法来检查字符串中的括号是否正确配对。该算法通过遍历字符串并利用栈数据结构来确保每种类型的括号（圆括号、方括号和花括号）都按正确的顺序关闭。

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Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.

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class Solution(object):
    def isValid(self, s):
        """
        :type s: str
        :rtype: bool
        """
        s_list = list(s)
        sstack = []
        for item in s_list:
            if item in ['{','(','[']:
                sstack.append(item)
            else:
                try:
                    if item == '}':
                        temp = sstack.pop()
                        if temp != '{':
                            return False
                    elif item == ')':
                        temp = sstack.pop()
                        if temp != '(':
                            return False
                    elif item == ']':
                        temp = sstack.pop()
                        if temp != '[':
                            return False
                except Exception,e:
                    return False
        if len(sstack) == 0:
            return True
        else:
            return False