#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<deque>
#include<set>
#include<map>
#include<ctime>
#define LL long long
#define inf 0x7ffffff
#define pa pair<int,int>
#define pi 3.1415926535897932384626433832795028841971
using namespace std;
inline LL read()
{
    LL x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
inline void write(LL a)
{
    if (a<0){printf("-");a=-a;}
    if (a>=10)write(a/10);
    putchar(a%10+'0');
}
inline void writeln(LL a){write(a);printf("\n");}
int n;
int a[100010];
LL ans;
struct p{int s,rnk;}b[100010];
inline bool operator <(p a,p b){return a.s>b.s;}
inline void work()
{
    n=read();ans=0;
    memset(a,0,sizeof(a));
    memset(b,0,sizeof(b));
    for (int i=1;i<=n;i++)a[i]=read();
    for (int i=1;i<n;i++)b[i].s=abs(a[i]-a[i+1]),b[i].rnk=i;
    sort(b+1,b+n);
    for (int i=1;i<=n;i++)
    {
        if (i==1)
        {
            if (b[1].rnk==1)ans+=b[2].s;
            else ans+=b[1].s;
        }else 
        if (i==n)
        {
            if (b[1].rnk==n-1)ans+=b[2].s;
            else ans+=b[1].s;
        }else
        {
            int cnt=1;
            while (b[cnt].rnk==i-1||b[cnt].rnk==i)cnt++;
            ans+=max(b[cnt].s,abs(a[i-1]-a[i+1]));
        }
    }
    printf("%I64d\n",ans);
}
int main()
{
    int T=read();
    while (T--)work();
}