LeetCode--Combinations

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.

For example,
If n = 4 and k = 2, a solution is:

[  [2,4],  [3,4],  [2,3],  [1,2],  [1,3],  [1,4],]

#include<vector>using std::vector;class Solution {public:vector<vector<int> > combine(int n, int k) {vector<vector<int>> res;vector<int> temp(k,0);get_res(0,0,k,n,res,temp);return res;}void get_res(int data,int now, int k, int n, vector<vector<int>>& res, vector<int>& temp){if(k == now){res.push_back(temp);return;}for(int i = data+1; i <= n-k+now+1; i++){temp[now] = i;get_res(i,now+1,k,n,res,temp);}return;}};