20 Valid Parentheses

最新推荐文章于 2024-11-22 06:42:51 发布

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本文介绍了一个使用栈数据结构实现的有效括号匹配算法。该算法能够判断由'()', '[]', '{}

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.

记得玩过一个手机游戏，叫做《黑客》，也有这个匹配括号的题。

class Solution {
public:
    bool isValid(string s) {
        if (s.length() % 2)
        {
            return false;
        }    
        stack<char> brackets;
        int i = 0;
        while (i < s.length())
        {
            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;
    }
};