#include <stdio.h>
int main()
{
    int x, y, z,i, max,min,d;
    scanf("%d",&x);
    while (x--)
    {
        scanf("%d",&y);
        max=0;
        min=50000;
        for (i=0;i<y;i++)
        {
            scanf("%d",&z);
            if (max<z) max=z;
            if (min>z) min=z;
        }
        d=(max-min)*2;
        printf("%d\n",d);
    }
    return 0;
}