Two Repeated Elements

{
#include<bits/stdc++.h>
using namespace std;
//Position this line where user code will be pasted.

void twoRepeated(int arr[], int n){
    
    // Your code here
    for(int i=0;i<n+2;i++) {
        if(arr[abs(arr[i])] > 0)
            arr[abs(arr[i])] *= -1;
        else 
        cout << abs(arr[i]) << " ";
        }
   
}
int main()
{
    int t,n;
    cin>>t;
    
    while(t--)
    {
        cin>>n;
        
        int a[n+2];
        
        for(int i=0;i<n+2;i++)
            cin>>a[i];
        
        twoRepeated(a, n);
        cout<<endl;
    }
    return 0;
}