public class Solution {

public ArrayList<ArrayList<Integer>> subsets(int[] S) {

// Start typing your Java solution below

// DO NOT write main() function

Arrays.sort(S);

ArrayList<ArrayList<Integer>> ans = new ArrayList<ArrayList<Integer>>();

if(S.length==0) return ans;

int kk = 0;

kk = 1 << (S.length);

for(int i=0;i<kk;i++){

ArrayList<Integer> tmp = new ArrayList<Integer>();

int digit = 0;

int k = i;

int index = 0;

while(index<S.length){

digit = k & 1;

k >>= 1;

if(digit==0){

tmp.add(S[index]);

}

index++;

}

ans.add(tmp);

}

return ans;

}

}