#include<stdio.h>

//#include<bits/stdc++.h>

#include<string.h>

#include<iostream>

#include<math.h>

#include<sstream>

#include<set>

#include<queue>

#include<map>

#include<vector>

#include<algorithm>

#include<limits.h>

#define inf 0x3fffffff

#define INF 0x3f3f3f3f

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define LL long long

#define ULL unsigned long long

using namespace std;

long long n,m;

long long a[100005];

long long q,p;

long long b[100005],e[100005],c[100005];

long long sum=0;

int t;

long long MAXN1,MAXN2;

int main()

{

    scanf("%d",&t);

    while(t--)

    {

        sum=0;

        memset(b,0,sizeof(b));

        memset(c,0,sizeof(c));

        memset(e,0,sizeof(e));

        scanf("%d",&n);

        for(int i=1; i<=n; i++)

        {

            scanf("%d",&a[i]);

        }

        MAXN1=0;

        MAXN2=0;

        for(int i=3; i<=n; i++)

        {

            MAXN1=max(MAXN1,abs(a[i-2]-a[i-1]));

            c[i]=MAXN1;

        }

        for(int i=n-2; i>=1; i--)

        {

            MAXN2=max(MAXN2,abs(a[i+2]-a[i+1]));

            b[i]=MAXN2;

        }

        for(int i=2; i<=n-1; i++)

        {

            e[i]=abs(a[i-1]-a[i+1]);

        }

        for(int i=2; i<=n-1; i++)

        {

            sum+=max(e[i],max(c[i],b[i]));

        }

        sum+=(b[1]+c[n]);

        printf("%lld\n",sum);

    }

    return 0;

}