#include<stdio.h>
#include<algorithm>
#include<string.h>
#define N 100050
using namespace std;
long long jilu[N];
long long af[N],bf[N];
int main()
{
    int t;
    scanf("%d",&t);
    while(t--){
        memset(bf,0,sizeof(bf));
        memset(af,0,sizeof(af));
        int n;
        scanf("%d",&n);
        long long ans=0;
        for(int i=1;i<=n;i++){
            scanf("%I64d",jilu+i);
            if(i>1)
                bf[i]=max(bf[i-1],max(jilu[i]-jilu[i-1],jilu[i-1]-jilu[i]));
        }
        for(int i=n-1;i>=1;i--){
            af[i]=max(af[i+1],max(jilu[i+1]-jilu[i],jilu[i]-jilu[i+1]));
        }
        ans+=af[2];
        for(int i=2;i<n;i++){
            ans+=max(max(bf[i-1],af[i+1]),max(jilu[i-1]-jilu[i+1],jilu[i+1]-jilu[i-1]));
        }
        ans+=bf[n-1];
        printf("%I64d\n",ans);
    }
}