题解在此

#include <iostream>
#include <algorithm>
using namespace std;
int a[100010];
int main(){
    int n;
    cin>>n;
    for (int i=1;i<=n;i++){
        cin>>a[i];
    }
    sort(a+1,a+1+n,greater<int>());
    cout<<a[1]*a[1]*a[1]+a[2]*a[2]+a[3];
    return 0;
}