Fork me on GitHub

20 - 有效的括号

发表于 | 分类于

题目描述

方法

数据结构经典题，用栈完美解决。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
class Solution:
    def isValid(self, s):
        """
        :type s: str
        :rtype: bool
        """

        if s is None:
        	return false

        x = ['[','(','{']
        y = ["]",")","}"]
        z = ["()","[]","{}"]

        stack = []
        for char in s:
        	if char in x:
        		stack.append(char)
        	elif char in y:
        		if len(stack) == 0:
        			return False
        		else:
        			temp = stack.pop(-1) + char
        			if temp not in z:
        				return False
        if len(stack) != 0:
        	return False	
        return True