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++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
using namespace std ;
typedef long long int ll;
int main()
{
   ll a,b,c,d,p;
   cin>>a>>b>>c>>d;
   if(a>0&&b>0&&c>0&&d>0)
   {
       p=max(a,b)*max(c,d);
   }
   if(a<0&&b<0&&c<0&&d<0)
   {
       p=max(abs(a),abs(b))*max(abs(c),abs(d));
   }
   if(a>0&&b>0&&c<0&&d>0)
    p=b*d;
   if(c>0&&d>0&&a<0&&b>0)
    p=d*b;
   if(a<0&&c<0&&b>0&&d>0)
    p=(max((a*c),(c*d)));
   if((a<0&&c<0&&d<0&&b>0)||(a<0&&b<0&&c<0&&d>0))
    p=a*c;



    cout<<p<<endl;

}