https://www.luogu.com.cn/team/121992

using namespace std;
long long n,a[200010],ans,l,r;
int main()
{
	freopen("maxarea.in","r",stdin); 
	freopen("maxarea.out","w",stdout); 
	cin>>n;
	for(int i=1;i<=n;i++) cin>>a[i];
	l=1;r=n;
	while(l<r)
	{
		ans=max(ans,min(a[l],a[r])*(r-l));
		if(a[l]<a[r]) l++;
		else r--;
	}
	cout<<ans;
}