Combinations
Desicription
Given two integers n and k, return all possible combinations of k numbers out of 1 … n.
For example,
If n = 4 and k = 2, a solution is:
代码语言：javascript复制[
[2,4],
[3,4],
[2,3],
[1,2],
[1,3],
[1,4],
]Solution
代码语言：javascript复制class Solution {
public:
vector<vector<int>> combine(int n, int k) {
vector<vector<int>> res;
vector<int> tmp(k, 0);
int index = 0;
while(index >= 0){
tmp[index] ;
if(tmp[index] > n)
index--;
else if(index == k - 1)
res.push_back(tmp);
else
index , tmp[index] = tmp[index - 1];
}
return res;
}
};
