Leetcode Combinations

题意：列出组合。

思路：DFS。

class Solution {
public:
    vector<vector<int> > re;
    int n, k;
    vector<vector<int>> combine(int n, int k) {
        this->n = n;
        this->k = k;
        
        
            vector<int> temp;
            dfs(temp, 1, k);
        
        
        return re;
    }
    int dfs(vector<int> temp, int s, int depth) {
        if(depth == 0) {
            re.push_back(temp);
            return 0;
        }
        vector<int> temp2;
        for(int i = s; i <= this->n ; ++ i) {
            temp2 = temp;
            temp2.push_back(i);
            dfs(temp2, i + 1, depth - 1);
        }
        
        return 0;
    }
};