Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets.

Note: The solution set must not contain duplicate subsets.

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

[ [2], [1], [1,2,2], [2,2], [1,2], [] ]

Solution

public class Solution {
     public List<List<Integer>> subsetsWithDup(int[] nums) {
        List<List<Integer>> result = new ArrayList<>();
        Arrays.sort(nums);
        subset(nums, 0, nums.length, new ArrayList<>(), result);
        return result;
    }

    public void subset(int[] nums, int start, int size, List<Integer> current, List<List<Integer>> total) {
        total.add(new ArrayList<Integer>(current));

        for (int i = start; i < size; i++) {
            if (i == start || nums[i] != nums[i - 1]) {
                current.add(nums[i]);
                subset(nums, i+1, size, current, total);
                current.remove(current.size() - 1);
            }
        }
    }
}