2021 TS10 DANANG B1. Tích lớn nhất

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define LT "a"
#define maxn 10005

int n;
ll a[maxn];

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

}

void solve() {
    sort(a + 1, a + n + 1);
	ll ans = -1e18;
	ans = max(ans, a[1] * a[2]);
	ans = max(ans, a[n] * a[n - 1]);
	ans = max(ans, a[n] * a[n - 1] * a[n - 2]);
	ans = max(ans, a[1] * a[2] * a[n]);
	cout << ans << endl;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    freopen(LT".inp", "r", stdin);
    freopen(LT".out", "w", stdout);
    init();
    solve();
}