Problem:
Score : 200 points

Problem Statement

Given are integers a,b,c and d.
If x and y are integers and a \leq x \leq b and c\leq y \leq d hold, what is the maximum possible value of x \times y?

Constraints

-10^9 \leq a \leq b \leq 10^9

-10^9 \leq c \leq d \leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

a b c d

Output

Print the answer.

Sample Input 1

1 2 1 1

Sample Output 1

2

If x = 1 and y = 1 then x \times y = 1.
If x = 2 and y = 1 then x \times y = 2.
Therefore, the answer is 2.

Sample Input 2

3 5 -4 -2

Sample Output 2

-6

The answer can be negative.

Sample Input 3

-1000000000 0 -1000000000 0

Sample Output 3

1000000000000000000

Solution in C# (.NET Core 3.1.201) (judge verdict: Accepted)


using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Schema;

class IDONTKNOWCSHARP
{

    public static void Main()
    {
        long[] values = Convert(GetLines());

        long[] test = new long[4];
        test[0] = values[0] * values[2];
        test[1] = values[0] * values[3];
        test[2] = values[1] * values[2];
        test[3] = values[1] * values[3];

        long max = long.MinValue;
        foreach (long value in test)
        {
            if (value > max)
                max = value;
        }


        Console.WriteLine(max);
 //      Console.ReadLine();
    }


    static long[] Convert(string[] v)
    {
        var temp = new long[v.Length];

        for (int i = 0; i < temp.Length; i++)
        {
            temp[i] = long.Parse(v[i]);
        }

        return temp;
    }


    static string[] GetLines()
    {
        return Console.ReadLine().Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
    }
}