#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<iostream>

using namespace std;

int t , n , a[200000];

int main() {
    scanf( "%d" , &t );
    while( t-- ) {
        scanf( "%d" , &n );
        for( int i = 0 ; i < n ; i++ )
            scanf( "%d" , &a[i] );
        int firmax = -1 , secmax = -1 , thimax = -1;
        for( int i = 1 ; i < n ; i++ ) {
            int cur = abs( a[i]-a[i-1] );
            if( cur > firmax ) {
                thimax = secmax;
                secmax = firmax;
                firmax = cur;
            }
            else if( cur > secmax ) {
                thimax = secmax;
                secmax = cur;
            }
            else if( cur > thimax ) {
                thimax = cur;
            }
        }
        long long ans = 0;
        for( int i = 1 ; i+1 < n ; i++ ) {
            int pre = abs( a[i]-a[i-1] ) , nex = abs( a[i]-a[i+1] ) , cur = abs( a[i+1]-a[i-1] );
            int maxx = max( pre , nex ) , minn = min( pre , nex );
            if( maxx == firmax ) {
                if( minn == secmax ) {
                    ans += max( cur , thimax );
                }
                else {
                    ans += max( cur , secmax );
                }
            }
            else {
                ans += max( cur , firmax );
            }
        }
        int pre = abs( a[1]-a[0] );
        if( pre == firmax )
            ans += secmax;
        else
            ans += firmax;
        pre = abs( a[n-1]-a[n-2] );
        if( pre == firmax )
            ans += secmax;
        else
            ans += firmax;
        cout << ans << endl;
    }
    return 0;
}