子集

[1,2,3]

[
[3],
[1],
[2],[1,2,3],
[1,3],
[2,3],
[1,2],
[]
]

class Solution {
public:
/*
* @param nums: A set of numbers
* @return: A list of lists
*/
vector<vector<int>> subsets(vector<int> &nums) {
// write your code here
vector<vector<int>> numsets;
vector<int> numset;
subsets(nums, numsets, numset, 0);
return numsets;
}
void subsets(const vector<int> &nums,
vector<vector<int>> &numsets,
vector<int> numset,
int pos) {
numsets.push_back(numset);
for (int i = pos; i < nums.size(); i++) {
numset.push_back(nums[i]);
subsets(nums, numsets, numset, i + 1);
numset.pop_back();
}
}
};