#include<cstdio>
#include<cstring>
#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<set>
#include<list>
#include<queue>
#include<stack>
#include<string>
#include<cstring>
using namespace std;

int a[100006];
int b[100006];

int main()
{
    int t;
    scanf("%d",&t);
    while (t--)
    {
        int n,mx=0,k=0;
        scanf("%d",&n);
        for (int i=0;i<n;i++) scanf("%d",&a[i]);
        for (int i=0;i<n-1;i++)
        {
            b[i]=abs(a[i+1]-a[i]);
            if (b[i]>mx)
            {
                mx=b[i];
                k=i;
            }
        }
        long long ans=0;
        int cut=0;
        if (mx!=b[0]) ans+=mx;
        else
        {
            for (int i=1;i<n-1;i++) cut=max(cut,b[i]);
            ans+=cut;
        }

        cut=0;
        if (mx!=b[n-2]) ans+=mx;
        else
        {
            for (int i=0;i<n-2;i++) cut=max(cut,b[i]);
            ans+=cut;
        }

        for (int i=1;i<n-1;i++)
        {
            cut=abs(a[i+1]-a[i-1]);
            if (i==k||i==k+1)
            {
                for (int j=0;j<n-1;j++)
                {
                    if (j==i||j==i-1) continue;
                    cut=max(cut,b[j]);
                }
            }
            else cut=max(cut,mx);
            ans+=cut;
        }
        printf("%I64d\n",ans);
    }
}