LeetCode: 20. Valid Parentheses

题目：

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.

题意：

配对括号是否一致

题解：

class Solution(object):
def isValid(self, s):
"""
:type s: str
:rtype: bool
"""
cur=[]
count=0
for i in range(len(s)):
if s[i] in [')', ']', '}'] and count==0:
return False
if s[i] in ['(', '[', '{']:
cur.append(s[i])
count=count+1
elif (count>0) and (s[i]==')' and cur[count-1]=='(') or (s[i]==']' and cur[count-1]=='[') or (s[i]=='}' and cur[count-1]=='{'):
del cur[count-1]
count=count-1
else:
return False
if count==0:
return True
else:
return False