LeetCode – Refresh – Combinations

Same algorithm with combination. Input as the (1..n), constraint is that the length of each combine should be k.

 1 class Solution {
 2 public:
 3     void getComb(vector<vector<int> > &result, vector<int> current, int n, int k, int start) {
 4         if (current.size() == k) {
 5             result.push_back(current);
 6             return;
 7         }
 8         for (int i = start; i <= n; i++) {
 9             current.push_back(i);
10             getComb(result, current, n, k, i+1);
11             current.pop_back();
12         }
13     }
14     vector<vector<int> > combine(int n, int k) {
15         vector<vector<int> > result;
16         getComb(result, vector<int> (), n, k, 1);
17         return result;
18     }
19 };