subsets.java

// Given a set of distinct integers, nums, return all possible subsets.

// Note: The solution set must not contain duplicate subsets.

// For example,
// If nums = [1,2,3], a solution is:

// [
//   [3],
//   [1],
//   [2],
//   [1,2,3],
//   [1,3],
//   [2,3],
//   [1,2],
//   []
// ]

public class Solution {

    public List<List<Integer>> subsets(int[] nums) {
        
        List<List<Integer>> result = new ArrayList<>();
        
        recurse(result, nums, new Stack<>(), 0);
        
        return result;
        
    }
    
    
    private void recurse(List<List<Integer>> result, int[] nums, Stack path, int position) {
        
        if(position == nums.length) {
            
            result.add(new ArrayList<>(path));
            return;
            
        }
        
        
        path.push(nums[position]);
        recurse(result, nums, path, position + 1);
        
        path.pop();
        
        recurse(result, nums, path, position + 1);
        
    }
   
}