MAXENERGY C++

#include<bits/stdc++.h>
#define oo 1000005
using namespace std;
const int maxN=1e6+5;
long long n,x,y,z,a[maxN],mid[maxN],mad[maxN],mic[maxN],mac[maxN];
long long ma=-400000000000;
int main()
{
    freopen("MAXENERGY.inp","r",stdin);
    freopen("MAXENERGY.out","w",stdout);
    scanf("%lld",&n);
    for (int i = 1 ;i<=n;i++)
    {
        scanf("%lld",&a[i]);
    }
    mid[0]=oo;mad[0]=-oo;
    for (int i = 1 ; i<=n;i++)
    {
        mid[i]=min(mid[i-1],a[i]);
        mad[i]=max(mad[i-1],a[i]);
    }
    mic[n+1]=oo;mac[n+1]=-oo;
    for (int i = n ; i>=1;i--)
    {
        mic[i]=min(mic[i+1],a[i]);
        mac[i]=max(mac[i+1],a[i]);
    }
    for (int i= 2 ;i<=n-1;i++)
    {
        ma=max(ma,(mad[i-1]-a[i])*(a[i]-mic[i+1]));
        ma=max(ma,(mid[i-1]-a[i])*(a[i]-mac[i+1]));
    }
    cout<<ma<<endl;
}