#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <cstdlib>

using namespace std;

typedef long long ll;

const int maxn = 100000 + 5;

int a[maxn], mx1[maxn], mx2[maxn];

int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {
        int n;
        scanf("%d", &n);
        for(int i = 1; i <= n; ++i)
        {
            scanf("%d", a + i);
            if(i > 1)
            {
                mx1[i] = max(mx1[i - 1], abs(a[i] - a[i - 1]));
            }
        }
        mx2[n] = 0;
        for(int i = n - 1; i > 0; --i)
        {
            mx2[i] = max(mx2[i + 1], abs(a[i + 1] - a[i]));
        }
        ll ans = mx2[2];
        ans += mx1[n - 1];
        for(int i = 2; i < n; ++i)
        {
            int tmp = abs(a[i + 1] - a[i - 1]);
            ans += max(tmp, max(mx1[i - 1], mx2[i + 1]));
        }
        printf("%I64d\n", ans);
    }
    return 0;
}