#include <bits/stdc++.h>
using namespace std;
int main()
{
int tee;
cin>>tee;
while(tee--)
{
int n,i,j;
cin>>n;
int a[n];
for( i=0;i<n;i++)
{
cin>>a[i];
}sort(a,a+n);
for( i=0;i<n;i++)
{
//for(j=i+1;j<n;j++)
if(a[i]==a[i+1])
{
cout<<a[i]<<" ";
}
}
cout<<endl;
}
// your code goes here
return 0;
}
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