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 <iostream>
#include <stdio.h>
#include<string>
#define NUM 3

using namespace std;
int main(){

long a,b,c,d,e,f,g,h,i;

cin >> a >> b >> c >> d;

e = a * c;
f = a * d;
g = b * c;
h = b * d;

long z[] ={e,f,g,h};
long max = z[0];

for(i=0;i<NUM;i++){
if(z[i] > max){
max = z[i];
}
}

cout << max << endl;

}