#include <cstdio>
#include <algorithm>
using namespace std;
int a[100010];
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]);
        int max1 = 0, max2 = 0, max3 = 0;
        for (int i = 1;i <= n-1;i++) {
            int cur = abs(a[i] - a[i+1]);
            if (cur >= max1) {
                max3 = max2;max2 = max1;max1 = cur;
            } else if (cur >= max2) {
                max3 = max2;max2 = cur;
            } else if (cur > max3) {
                max3 = cur;
            }
        }
        long long ans = 0;
        for (int i = 1;i <= n;i++) {
            if (i != 1 && i != n) {
                int new0 = abs(a[i+1] - a[i-1]);
                if (abs(a[i] - a[i-1]) == max1 && abs(a[i] - a[i+1]) == max2 || abs(a[i] - a[i-1]) == max2 && abs(a[i] - a[i+1]) == max1) {ans += max(max3, new0);continue;}
                if (abs(a[i] - a[i-1]) == max1 || abs(a[i] - a[i+1]) == max1) {ans += max(max2, new0);continue;}
                ans += max(new0, max1);
            } else if (i == 1) {
                ans += abs(a[2] - a[1]) == max1 ? max2 : max1;
            } else {
                ans += abs(a[n] - a[n-1]) == max1 ? max2 : max1;
            }
        }
        printf("%I64d\n", ans);
    }
    return 0;
}