class Solution{
public:
vector<int> duplicates(int arr[], int n) {
// code here
vector<int> v;
sort(arr,arr+n);
for(int i=0;i<n;i++)
{
if(arr[i]==arr[i+1])
{
v.push_back(arr[i]);
}
}
v.erase(unique(v.begin(),v.end()),v.end());
if(v.empty())
{
v.push_back(-1);
}
return v;
}
};