leetCode 穷竭搜索（结合实验楼）

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        vector<vector<int>> result;
        vector<int> list;
        if(nums.empty()) return result;
        sort(nums.begin(),nums.end());//用sort函数，为vector<int>里的元素排序
        dfs(nums,0,list,result);
        return result;
    }
    void dfs(vector<int>& nums,int p,vector<int>& list,vector<vector<int>>& result){
        result.push_back(list);
        for(int i=p;i<nums.size();i++){
            list.push_back(nums[i]);
            dfs(nums,i+1,list,result);
            list.pop_back();
        }
    }
};