Assignment Score

#include <bits/stdc++.h>
#include<vector>
#include<numeric>
using namespace std;

int main() {
    
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        vector<int> a(n);
        int sum=0;
        for(int i=0;i<n;i++){
            cin>>a[i];
            sum+=a[i];
        }
        int total=(n+1)*100;
        int required=total/2;
        int lastscore=required-sum;
        if(lastscore>100){
            cout<<-1<<endl;
        }
        else if(lastscore<=0){
            cout<<0<<endl;
        }
        else{
            cout<<lastscore<<endl;
        }
        

	// your code goes here
}
return 0;

}