18 - generate parentheses

最新推荐文章于 2021-02-25 17:37:50 发布

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本文介绍了一个使用深度优先搜索(DFS)算法生成所有有效括号组合的方法。针对输入的整数n，该算法能够生成所有可能的有效括号组合。示例中展示了当n等于3时的有效括号组合。

Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.

For example, given n = 3, a solution set is:

"((()))", "(()())", "(())()", "()(())", "()()()"

solutions: dfs，解这道题的时候leetcode不停报错internal error...晚点再测试

class Solution {
public:
    void generateResult(int left, int right, string result, vector<string> &res)
    {
        if(left == 0 && right == 0)
            res.push_back(result);
        
        if(left > 0)
            generateResult(left-1, right, result + "(", res);
        
        if(left < right)
            generateResult(left, right-1, result + ")", res);
            
    }

    vector<string> generateParenthesis(int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<string> res();
        if(n <= 0)
            return res;
        
        string result = "";
        
        generateResult(n, n, result, res);
        
        return res;
    }
};