package LeetCode;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

public class LeetCode77 {

    //https://leetcode-cn.com/problems/combinations/description/

    /// : O(n^k)
    /// : O(k)

    private ArrayList res;

    public List combine(int n, int k) {

        res = new ArrayList();
        if(n