The case is [-1,-1,3,-1] , The error is TLE

```
public class Solution {
ArrayList<ArrayList<Integer>> answerlist=new ArrayList<ArrayList<Integer>>();
public ArrayList<ArrayList<Integer>> permuteUnique(int[] num) {
permute(num,0);
return answerlist;
}
public void permute(int num[],int step)
{
if (step==num.length-1)
{
ArrayList<Integer> answer=new ArrayList<Integer>();
for (int i=0;i<num.length;i++) answer.add(num[i]);
answerlist.add(answer);
}
else
{
permute(num,step+1);
for (int i=step+1;i<num.length;i++)
{
if (num[step]==num[i]) continue;
int temp;
temp=num[step];
num[step]=num[i];
num[i]=temp;
permute(num,step+1);
temp=num[i];
num[i]=num[step];
num[step]=temp;
}
}
}
}
```