代码随想录算法训练营第二十四天| 77. 组合

77. 组合

题目链接
文章讲解

class Solution {
   
public:
    vector<vector<int>> ans;
    vector<int> group;

    void backtracking(int begin, const int& n, const int& k) {
   
        if (group.size() == k) {
   
            ans.push_back(group);
            return;
        }
        int end = n - (k - group.size()) + 1;
        for (int i = begin; i <= end; i++) {
   
            group.push_back(i);
            backtracking(i + 1, n, k);
            group.pop_back();
        }
    }

    vector<vector<int>> combine(int n, int k) {
   
        backtracking(1, n, k);
        return ans;
    }
};