#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<map>
#include<set>
#include<vector>
#include<bitset>

#define F first
#define S second
#define mp make_pair
using namespace std;
typedef __int64 LL;
const int maxn = 1e5 + 10;

LL h[maxn];
LL maxsum[maxn][25];
void RMQ(int n)
{
    for(int j=1; j<=20; j++)
        for(int i=1; i<=n; i++)
        {
            if(i+(1<<(j-1))<=n)
            {
                maxsum[i][j]=max(maxsum[i][j-1],maxsum[i+(1<<(j-1))][j-1]);
                //minsum[i][j]=min(minsum[i][j-1],minsum[i+(1<<(j-1))][j-1]);
            }
        }
}
int main()
{
    int T,n,k,q;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n);
        for(int i=1; i<=n; i++)
            scanf("%I64d",&h[i]);
        for(int i=1;i<=n-1;i++)
        {
            maxsum[i][0]=abs(h[i+1]-h[i]);
        }
        RMQ(n-1);
        LL ans=0;
        k=log10(n-1-2+1.0)/log10(2.0);
        ans+=max(maxsum[2][k],maxsum[n-1-(1<<k)+1][k]);
        k=log10(n-2-1+1.0)/log10(2.0);
        ans+=max(maxsum[1][k],maxsum[n-2-(1<<k)+1][k]);
        LL sum1,sum2,sum3;
        for(int i=2;i<=(n-1);i++)
        {
            sum1=sum2=sum3=0;
            if(i-2>=1)
            {
                k=log10(i-2-1+1.0)/log10(2.0);
                sum1=max(maxsum[1][k],maxsum[i-2-(1<<k)+1][k]);
            }
            if(i+1<=n-1)
            {
                k=log10(n-1-i-1+1.0)/log10(2.0);
                sum2=max(maxsum[i+1][k],maxsum[n-1-(1<<k)+1][k]);
            }
            sum3=abs(h[i-1]-h[i+1]);
            ans+=max(max(sum1,sum2),sum3);
        }
        printf("%I64d\n",ans);
    }
    return 0;
}