Bit

vector<vector<int>> subsets(vector<int>& nums) {

sort(nums.begin(),nums.end());

int len=nums.size();

vector<vector<int>> ret;

vector<int> path;

for(int i=0;i<(1<<len);i++){

path.clear();

for(int j=0;j<len;j++){

if(i&(1<<j))

path.push_back(nums[j]);

}

ret.push_back(path);

}

return ret;

}