public static void main(String[] args){

int[] num = new int[]{1,1,2};

List<List<Integer>> result = allsort(num);

System.out.println(result);

}

public static List<List<Integer>> allsort(int[] nums) {

if(nums.length == 0) return new ArrayList<>();

Arrays.sort(nums);

List<List<Integer>> lists = new ArrayList<>();

int[] visited = new int[nums.length];

util( visited,nums, lists, new ArrayList<>());

return lists;

}

public static void util(int[] visited, int[] nums, List<List<Integer>> lists, List<Integer> list ) {

if (list.size() == nums.length) {

lists.add(new ArrayList<>(list));

return;

}

for(int i = 0; i < nums.length ; i++) {

if(visited[i] == 1 || (i > 0 && visited[i-1] == 0 && nums[i-1] == nums[i])) continue;

visited[i] = 1;

list.add(nums[i]);

util(visited,nums, lists, list);

list.remove(list.size() -1);

visited[i] = 0;

}

}