20. Valid Parentheses
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.
【思路】
1、数据结构类题目,考查栈概念的运用
2、遍历字符串,使用一个栈结构存储左括号,每碰到一个右括号与之对比,全部一一匹配且栈为空视为True,否则为False
3、使用python解题,“一一匹配”,利用字典结构实现
【参考代码_Runtime:44ms】
class Solution:
def isValid(self, s):
"""
:type s: str
:rtype: bool
"""
dict={')':'(','}':'{',']':'['}
temp=[]
for item in s:
if item in dict:
if len(temp)!=0 and dict[item]==temp[-1]:
temp.pop()
else:
return False
else:
temp.append(item)
if len(temp)==0:
return True
else:
return False