#include <iostream>#include "matrix.h"using namespace std;int main(void) { long unsigned int highest = 0; for ( unsigned int y = 0; y < 20; y++ ) { for ( unsigned int x = 0; x < 17; x++ ) { long unsigned product = 1; for ( unsigned int i = x; i < x + 4; i++ ) { product *= matrix[y][i]; } if ( product > highest ) { highest = product; } } } for ( unsigned int x = 0; x < 20; x++ ) { for ( unsigned int y = 0; y < 17; y++ ) { long unsigned product = 1; for ( unsigned int i = y; i < y + 4; i++ ) { product *= matrix[i][x]; } if ( product > highest ) { highest = product; } } } for ( unsigned int y = 0; y < 18; y++ ) { for ( unsigned int x = 0; x < 17; x++ ) { long unsigned int product = 1; for ( unsigned int i = 0; i < 4; i++ ) { product *= matrix[y+1][x+1]; } if ( product > highest ) { highest = product; } } } cout << highest << endl;}