leetcode Valid Parentheses python

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leetcode Valid Parentheses python

# 解题思路: # 创建一个字典映射关系 dicts# 使用一个栈stk 遍历字符串s 得到一个新的字符串curItem 如果lastItem在dicts中的value和它相等不做任何操作# 如果不等入栈有lastItem的先append lastItem 然后是curItem ## 最后判断如果stk为空说明所给字符串匹配 return true class Solution(object): def isValid(self, s): """ :type s: s…

[LeetCode] Valid Parentheses 验证括号

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 "([)]"…

LeetCode: Valid Parentheses 解题报告

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 "(]" a…

[Leetcode] valid parentheses 有效括号对

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:给…

leetcode Longest Valid Parentheses python

class Solution(object): def longestValidParentheses(self, s): """ :type s: str :rtype: int """ maxlen=0 stack=[] last=-1 for i in range(len(s)): if s[i] == '(': stack.append(i) else: if stack == []: last=i else: stack.pop() i…

[leetcode]Valid Palindrome @ Python

原题地址:https://oj.leetcode.com/problems/valid-palindrome/ 题意: Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a c…

[leetcode]Valid Number @ Python

原题地址:http://oj.leetcode.com/problems/valid-number/ 题意:判断输入的字符串是否是合法的数. 解题思路:这题只能用确定有穷状态自动机(DFA)来写会比较优雅.本文参考了http://blog.csdn.net/kenden23/article/details/18696083里面的内容,在此致谢! 首先这个题有9种状态: 0初始无输入或者只有space的状态1输入了数字之后的状态2前面无数字,只输入了dot的状态3输入了符号状态4前面有数字和有do…