leetcode 77.组合

class Solution {
public:
    vector<vector<int>> result;
    vector<int> cur;
    void getR(int n,int k,int beginIndex){
        if(cur.size()==k){
            result.push_back(cur);
            return;
        }
        for(int i=beginIndex;i<=n;i++){
            cur.push_back(i);
            getR(n,k,i+1);
            cur.pop_back();
        }
    } 
    vector<vector<int>> combine(int n, int k) {
        result.clear();
        cur.clear();
        getR(n,k,1);
        return result;
    }
};

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