LeetCode 20 Valid Parentheses

2015-11-21 00:55:07 · 作者: · 浏览: 5

翻译

给定一个只包含'(', ')', '{', '}', '[' 和']'的字符串,判断这个输入的字符串是否是有效的。

括号必须在正确的形式下闭合,() 和()[]{} 是有效的,但是 (] 和([)] 则不是。

原文

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.

代码

class Solution {
public:
    bool isValid(string s) {
        if(s.size() % 2 != 0) return 0;
        stack
   
     brackets; int i = 0; while(i < s.size()) { if(brackets.empty()) { brackets.push(s[i]); } else { if((brackets.top() == '(' && s[i] == ')') || (brackets.top() == '[' && s[i] == ']') || (brackets.top() == '{' && s[i] == '}')) { brackets.pop(); } else { brackets.push(s[i]); } } i ++; } return brackets.size() == 0; } };
   

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