Given a sequence nums that can contain repeated numbers, return all non-repeated permutations in any order.
Example 1:
Input: nums = [1,1,2]
Output:
[[1,1,2],
[1,2,1],
[2,1,1]]
Example 2:
Input: nums = [1 ,2,3]
Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3 ,2,1]]
class Solution {
public List<List<Integer>> permuteUnique(int[] nums) {
Arrays.sort(nums);
int lev=1;
List<List<Integer>> res = new ArrayList();
boolean[] pau = new boolean[nums.length];
Deque<Integer> que = new LinkedList();
back(nums,que,lev,pau,res);
return res;
}
public void back(int[] nums,Deque<Integer> que,int lev,boolean[] pau,List<List<Integer>> res){
if(lev>nums.length){
res.add(new ArrayList(que));
return;
}
for(int i=0;i<nums.length;i++){
if(pau[i]){
continue;
}
if(i>0&&nums[i]==nums[i-1]&&!pau[i-1]){
continue;
}
que.addLast(nums[i]);
pau[i]=true;
back(nums,que,lev+1,pau,res);
que.removeLast();
pau[i]=false;
}
}
}