Leetcode 77 Solution

This article provides solution to leetcode question 77 (combinations)

https://leetcode.com/problems/combinations

Solution

class Solution { vector<int> res; vector<vector<int>> m_res;
public: void generate(vector<int>& a, int start, int k) { if (res.size() == k) { m_res.push_back(res); return; }
for (int i = start; i < a.size(); i++) { res.push_back(a[i]); generate(a, i + 1, k); res.pop_back(); } }
vector<vector<int>> combine(int n, int k) { vector<int> a; for (int i = 1; i <= n; i++) a.push_back(i);
generate(a, 0, k);
return m_res; } };