#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<vector>
#include<queue>
#include<set>
#include<cmath>
#define logk(x) (int)(log(double(x))/log(2.0))
using namespace std;
const int MAXN = 100000+100;
int a[MAXN],max1[MAXN];

bool cmp(int a,int b){
    return a>b;
}

void solve(){
    int n;
    long long sum=0;
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d",&a[i]);
        if(i!=0){
            max1[i]=abs(a[i]-a[i-1]);
        }
    }
    int current_max;
    sort(max1+1,max1+n,cmp);
    for(int i=0;i<n;i++){
        if(i==0){
            if(max1[1]==abs(a[i+1]-a[i])){
                sum+=1LL*max1[2];
            }
            else sum+=1LL*max1[1];
        }
        else if(i==n-1){
            if(max1[1]==abs(a[i]-a[i-1])) sum+=1LL*max1[2];
            else sum+=1LL*max1[1];
        }
        else{
            if((abs(a[i]-a[i-1])==max1[1]&&abs(a[i+1]-a[i])==max1[2])||(abs(a[i]-a[i-1])==max1[2]&&abs(a[i+1]-a[i])==max1[1])){
                if(n>3)current_max=max(abs(a[i+1]-a[i-1]),max1[3]);
                else current_max=abs(a[i+1]-a[i-1]);
                sum+=1LL*current_max;
            }
            else if(abs(a[i]-a[i-1])==max1[1]||abs(a[i+1]-a[i])==max1[1]){
                if(n>3)current_max=max(abs(a[i+1]-a[i-1]),max1[2]);
                else current_max=abs(a[i+1]-a[i-1]);
                sum+=1LL*current_max;
            }
            else{
                if(n>3)current_max=max(abs(a[i+1]-a[i-1]),max1[1]);
                else current_max=abs(a[i+1]-a[i-1]);
                sum+=1LL*current_max;
            }
        }
    }
    cout<<sum<<endl;
}

int main(){
    int T;
    scanf("%d",&T);
    while(T--){
        solve();
    }
}