78. Subsets

dfs搜索很简单！ faster than 100% 开心

class Solution {
public:
	vector<vector<int>>res;
	vector<int>sub;
	void dfs(vector<int>& nums,int index) {
		for (int i = index; i < nums.size(); ++i) {
			sub.push_back(nums[i]);
			res.push_back(sub);
			dfs(nums, i + 1);
			sub.pop_back();
		}
	}
	vector<vector<int>> subsets(vector<int>& nums) {
		res.push_back(sub);
		dfs(nums, 0);
		return res;
	}
};