C :

#include<stdio.h>
int fun(int y1,int y2,int y3,int y4)
{return ((y1+y2)*y3+y4);}
int main()
{
	int T,max,y[5],s[12],i,p=0;
	scanf("%d",&T);
	while(T--)
	{
		for(i=0;i<4;i++)
			scanf("%d",&y[i]);
		s[0]=fun(y[0],y[1],y[2],y[3]);
		s[1]=fun(y[0],y[1],y[3],y[2]);
		s[2]=fun(y[0],y[2],y[1],y[3]);
		s[3]=fun(y[0],y[2],y[3],y[1]);
		s[4]=fun(y[0],y[3],y[1],y[2]);
		s[5]=fun(y[0],y[3],y[2],y[1]);
		s[6]=fun(y[1],y[2],y[0],y[3]);
		s[7]=fun(y[1],y[2],y[3],y[0]);
		s[8]=fun(y[1],y[3],y[2],y[0]);
		s[9]=fun(y[1],y[3],y[0],y[2]);
		s[10]=fun(y[2],y[3],y[0],y[1]);
		s[11]=fun(y[2],y[3],y[1],y[0]);
		max=s[0];
		for(i=1;i<12;i++)
			if(s[i]>max)
				max=s[i];
		printf("Case %d: %d\n",++p,max);
	}
	return 0;
}

C++ :

#include<iostream>
using namespace std;
int main()
{
	int n;
	cin >> n;
	int flag = 0;
	while (n--){
		flag++;
		int a[4];
		for (int i = 0; i < 4; i++)
			cin >> a[i];
		int sum = -99999;
		for (int i = 0; i < 4; i++)
		for (int j = 0; j < 4; j++)
		{
			if (j == i)
				continue;
			for (int l = 0; l < 4; l++)
			{
				if (l == j || l == i)
					continue;

				for (int f = 0; f < 4; f++){
					if (f == i || f == j || f == l)
						continue;
					if (sum < (a[i] + a[j])*a[l] + a[f])
						sum = (a[i] + a[j])*a[l] + a[f];
				}
			}
		}
		cout <<"Case "<<flag<<": "<< sum << endl;
	}
}