Array Subsets LeetCode (Subset of an array with Unique Elements- Power Set)

Given an integer array nums of unique elements, return all possible subsets (the power set).

The solution set must not contain duplicate subsets. Return the solution in any order.

 

Example 1:

Input: nums = [1,2,3]
Output: [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]

Example 2:

Input: nums = [0]
Output: [[],[0]]

 

NOTE:

• 1 <= nums.length <= 10
• -10 <= nums[i] <= 10
• All the numbers of nums are unique.

This problem is popular in LeetCode, GeeksForGeeks, and StackOverflow 

Solution:

 

	/**
	ArraySubsets:
	Given a set of distinct integers, nums, return all possible subsets (the power set).
	Note: The solution set must not contain duplicate subsets.
	Example:
	Input: nums = [1,2,3]
	Output:
	[
	[3],
	[1],
	[2],
	[1,2,3],
	[1,3],
	[2,3],
	[1,2],
	[]
	]
	*/
	import java.util.*;
	public class ArraySubsets{
	public static List<List<Integer>> subsets(int[] nums){
	List<List<Integer>> sets = new ArrayList<List<Integer>>();
	sets.add(new ArrayList<Integer>());
	if(nums.length==0){
	return sets;//empty set
	}
	//iterate and add the respective element to the subsets of previous iteration
	for(int i = 0; i<nums.length; i++){
	int size = sets.size();
	for(int j=0;j<size; j++){
	List<Integer> newlist = new ArrayList<>(sets.get(j));
	newlist.add(nums[i]);
	sets.add(newlist);
	}
	}
	return sets;
	}
	public static void main(String[] args){
	int[] nums = new int[]{1,2,3};
	List<List<Integer>> sets = subsets(nums);
	for(List<Integer> list:sets){
	System.out.println(Arrays.toString(list.toArray(new Integer[list.size()])));
	}
	}
	}

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