#pragma comment(linker, "/STACK:102400000,102400000")
#include <iostream>
#include <cstdio>
#include <cstring>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <vector>
#include <cmath>
#include <algorithm>
using namespace std;
const double eps = 1e-6;
const double pi = acos(-1.0);
const int INF = 1e9;
const int MOD = 1e9+7;
#define ll long long
#define CL(a,b) memset(a,b,sizeof(a))
#define lson (i<<1)
#define rson ((i<<1)|1)
#define N 100010
int gcd(int a,int b){return b?gcd(b,a%b):a;}

int n,m;
int a[N];
int aa,bb,cc;

int main()
{
    int T;
    int l,r;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n);
        ll sum = 0;
        aa=bb=cc=0;
        int p1=-1,p2=-1;
        for(int i=0; i<n; i++)
        {
            scanf("%d",&a[i]);
            if(i>0)
            {
                int d = abs(a[i]-a[i-1]);
                if(d > aa)
                    {
                        cc=bb;
                        bb=aa, p2=p1;
                        aa = d, p1 = i;
                    }
                else if(d > bb)
                    cc=bb,bb = d, p2 = i;
                else if(d > cc)
                    cc = d;
            }
        }
        if(p1 == 1) sum += bb;
        else sum += aa;
        if(p1 == n-1) sum += bb;
        else sum += aa;

        for(int i=2; i<n; i++)
        {
            int d = abs(a[i]-a[i-2]);
            if (p1==i-1||p1==i)
            {
                if(p2==i-1||p2==i)
                    sum += max(d, cc);
                else sum += max(d, bb);
            }
            else sum += max(d, aa);
        }
        cout<<sum<<endl;
    }
    return 0;
}