MMAX TS10 Da Nang 2021-2022

#define task "MMAX"

#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

using ll = long long;
using ld = long double;

constexpr int N = 1e5 + 5;
int n, a[N];

void Read()
{
    cin >> n;

    for (int i = 1; i <= n; ++i)
        cin >> a[i];
}

ll Haiso()
{
    return max(1ll * a[1] * a[2], 1ll * a[n - 1] * a[n]);
}

ll Baso()
{
    return max(1ll * a[n] * a[n - 1] * a[n - 2], 1ll * a[1] * a[2] * a[n]);
}

void Solve()
{
    sort(a + 1, a + n + 1);

    cout << max(Haiso(), Baso());
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }

    Read();
    Solve();
}