#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define N 500005
using namespace std;
typedef long long ll;
ll ans;
ll cas,i,n,a[N],tr[N];
void build(ll l,ll r,ll p)
{
    if (l==r)
    {
        tr[p]=abs(a[l+1]-a[l]);
        return;
    }
    ll mid=(l+r)/2;
    build(l,mid,p*2);
    build(mid+1,r,p*2+1);
    tr[p]=max(tr[p*2],tr[p*2+1]);
}
ll ask(ll l,ll r,ll x,ll y,ll p)
{
    if (x>y)return 0;
    //printf("%I64d %I64d %I64d %I64d %I64d\n",l,r,x,y,p);
    if (l==x && r==y)return tr[p];
    ll mid=(l+r)/2;
    if (y<=mid)return ask(l,mid,x,y,p*2);else
    if (x>mid) return ask(mid+1,r,x,y,p*2+1);else
        return max(ask(l,mid,x,mid,p*2),ask(mid+1,r,mid+1,y,p*2+1));
}
int main()
{
    scanf("%I64d",&cas);
    while (cas--)
    {
        scanf("%I64d",&n);
        for (i=1;i<=n;i++)scanf("%I64d",&a[i]);
        for (i=1;i<=n*4;i++)tr[i]=0;
        build(1,n-1,1);
        ans=0;
        ans=ask(1,n-1,2,n-1,1);
        ans+=ask(1,n-1,1,n-2,1);
        for (i=2;i<n;i++)
            ans+=max(abs(a[i+1]-a[i-1]),max(ask(1,n-1,1,i-2,1),ask(1,n-1,i+1,n-1,1)));
        printf("%I64d\n",ans);
    }
}