/*
problem link: https://www.codechef.com/LP1TO202/problems/MAKEEQUAL
*/
#include<iostream>
#include<climits>
#define ll long long
#include<vector>
#include<stack>
#include<string>
#include<algorithm>
using namespace std;
void solve()
{
ll n;
cin >> n;
vector<ll> v(n);
for (ll i = 0; i < n; i++)
{
cin >> v[i];
}
ll mn = INT_MAX, mx = INT_MIN;
for (ll i = 0; i < n; i++)
{
mn = min(mn, v[i]);
mx = max(mx, v[i]);
}
cout << mx - mn << "
";
}
int main()
{
int t;
cin >> t;
while (t--)
{
solve();
}
return 0;
}