/* -------------------------------- */
/* Name: Aseem Chakrabarthy */
/* Institute: CU */
/* Dept: CSE */
/* Email: aseem.cse.cu@gmail.com */
/* -------------------------------- */
#include <cstdio>
#include<iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <cctype>
#include <cstring>
#include <string>
#include <cstdlib>
#include <cmath>
#define M 10000000
bool prime[M];
typedef long long int ll;
using namespace std;
int main()
{
int test,store,distance;
cin>>test;
while(test--)
{
cin>>store;
int max=0;
int min=99;
while(store--)
{
cin>>distance;
if(max<=distance)//Finding maximum distance;
{
max=distance;
}
if(min>=distance)//Finding minimum distance;
{
min=distance;
}
}
int minimum_distance=(max-min)*2;//This problem to say that minimum distance for car
//parking to different shop.He can only one park.so i guess that (max-min)*2 is the
// minimum distance.Here multiply by 2 because he 1 time go to shop and again back.
cout<<minimum_distance<<endl;
}
}
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