package question;

import java.util.LinkedList;
import java.util.List;

public class Question46 {
 List<List<Integer>> res = new LinkedList<>();
 public List<List<Integer>> permute(int[] nums) {
 if (nums==null) return res;
 huiSu(new LinkedList<>(), nums);
 return res;
 }

 public void huiSu(List<Integer> list, int[] nums) {
 if (list.size()==nums.length) {
 res.add(new LinkedList<>(list));
 return;
 }
 for (int i = 0; i < nums.length; i++) {
 if (list.contains(nums[i])) continue;
 list.add(nums[i]);
 huiSu(list, nums);
 list.remove(list.size()-1);
 }
 }
}