# -*- coding: utf-8 -*-

class Solution:

# @param {string} s A string

# @return {boolean} whether the string is a valid parentheses

def isValidParentheses(self, s):

# Write your code here

par_list = []

for ch in s:

if (ch == '(') or (ch == '[') or (ch == '{'):

par_list.append(ch) # 插入左括号

else:

if not self.check(ch, par_list):

return False

return True if not par_list else False

def check(self, right, par_list):

if not par_list:

return False

left = par_list[-1]

if ((left == '(') and (right == ')')) or \

((left == '[') and (right == ']')) or \

((left == '{') and (right == '}')):

par_list.pop() # 括号匹配成功后弹出

else:

par_list.append(right)

return True