C++ :

#include<iostream>
#include<algorithm>
using namespace std;
const int N = 105;
int f[N][N]={0},a[N];
int main(){
	int n;
	cin>>n;
	for (int i=0;i<n;i++)
		cin>>a[i];
	for (int k=2;k<=n;k++)
		for (int i=0;i<n;i++)
			for (int j=1;j<k;j++)
	f[k][i]=max(f[k][i],f[j][i]+f[k-j][(i+j)%n]
	+a[i]*a[(i+j)%n]*a[(i+k)%n]);
		
	int ans=0;
	for (int i=0;i<n;i++)
		ans=max(ans,f[n][i]);
		cout<<ans<<endl;
		return 0;
}

Pascal :

var
n,i,j,k:longint;
max:int64;
a:array[-10..maxint] of int64;
f:array[1..1000,1..1000] of int64;
begin
{assign(input,'energy.in');
reset(input);
assign(output,'energy.out');
 rewrite(output);}

readln(n);
for i:=1 to n do
begin
read(a[i]);
a[n+i]:=a[i];
end;
for i:=2*n-1 downto 1 do
for j:=i+1 to 2*n do
for k:=i to j-1 do
if f[i,k]+f[k+1,j]+a[i]*a[k+1]*a[j+1]>f[i,j] then
begin
f[i,j]:=f[i,k]+f[k+1,j]+a[i]*a[k+1]*a[j+1] ;
if f[i,j]>max then max:=f[i,j];
end;
writeln(max div 2);

{close(input);
 close(output);}
end.