Subset Given a set of integer array nums without repeated elements, return all possible subsets of the array (power set)

Using bit operation, 1 means to select, 0 means not to select the element.

class Solution {
    
    
    public List<List<Integer>> subsets(int[] nums) {
    
    
    	ArrayList<List<Integer>> al = new ArrayList<List<Integer>>();
    	for(int i= 0;i<(1 << nums.length);i++) {
    
    
    		ArrayList<Integer> subal = new ArrayList<Integer>();
    		for(int j = 0;j < nums.length;j++) {
    
    
    			if(((i>>j) & 1)==1) subal.add(nums[j]);
    		}
    		al.add(subal);
    	}
		return al;
		
    }
}