#include<iostream>
using namespace std;
int main()
{
int n;
scanf("%d", &n);
while(n--)
{
int m, max = -1, min = 100;
scanf("%d", &m);
for( int i=0; i < m; i++ )
{
int a;
scanf("%d", &a);
if(a > max)
max = a;
if(a < min)
min = a;
}
printf("%d\n", (max-min) * 2);
}
return 0;
}