Subclasses

 1 public class Solution {

 2     public List<List<Integer>> permute(int[] num) {

 3         ArrayList<List<Integer>> result = new ArrayList<List<Integer>>();

 4         ArrayList<Integer> row = null;

 5         if(num == null ||num.length == 0) return result;

 6         long size = (long)Math.pow(2, num.length);

 7         for(long i = 0; i < size; i ++){

 8             row = new ArrayList<Integer>();

 9             for(int j = 0; j < num.length; j ++){

10                 if((i >> j) % 2 == 1) row.add(num[j]);

11             }

12             result.add(row);

13         }

14         return result;

15     }

16 }