//515MS	9976K
import java.math.BigInteger;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner cin=new Scanner(System.in);
		int t;
		t=cin.nextInt();
		for(int cas=1;cas<=t;cas++){
			BigInteger ans=BigInteger.valueOf(0);
			int n;
			n=cin.nextInt();
			BigInteger yanghui[]=new BigInteger[n];
			BigInteger s[]=new BigInteger[n+2];
			for(int i=0;i<n;i++)
				s[i]=cin.nextBigInteger();
			if (n == 1) {  
                System.out.println(s[0]);  
                continue;  
            }  
			yanghui[0]=BigInteger.valueOf(1);
			for(int i=1;i<n;i++){
				BigInteger x1=BigInteger.valueOf(i);
				BigInteger x2=BigInteger.valueOf(n-i);
				yanghui[i]=yanghui[i-1].multiply(x2).divide(x1);
			}
			boolean flag=true;
			for(int i=n-1;i>=0;i--){
				if(flag){ans=ans.add(yanghui[i].multiply(s[i]));flag=false;}
				else {ans=ans.subtract(yanghui[i].multiply(s[i]));flag=true;}
			}
			System.out.println(ans);		
		}
	}
}