Euler_11

/** In the 20×20 grid below, four numbers along a diagonal line have been marked in red.
The product of these numbers is 26 × 63 × 78 × 14 = 1788696.

What is the greatest product of four adjacent numbers in any direction
(up, down, left, right, or diagonally) in the 20×20 grid?
*/

public class EulerEleven


{
  public static void main ( String[] args )
  {
  int[][] board = {{8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8},
  			   {49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,04,56,62,0},
				   {81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,03,49,13,36,65},
				   {52,70,95,23,04,60,11,42,69,24,68,56,01,32,56,71,37,02,36,91},
				   {22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80},
				   {24,47,32,60,99,03,45,02,44,75,33,53,78,36,84,20,35,17,12,50},
				   {32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70},
				   {67,26,20,68,02,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21},
				   {24,55,58,05,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72},
				   {21,36,23,9,75,00,76,44,20,45,35,14,00,61,33,97,34,31,33,95},
				   {78,17,53,28,22,75,31,67,15,94,03,80,04,62,16,14,9,53,56,92},
				   {16,39,05,42,96,35,31,47,55,58,88,24,00,17,54,24,36,29,85,57},
				   {86,56,00,48,35,71,89,07,05,44,44,37,44,60,21,58,51,54,17,58},
				   {19,80,81,68,05,94,47,69,28,73,92,13,86,52,17,77,04,89,55,40},
				   {04,52,8,83,97,35,99,16,07,97,57,32,16,26,26,79,33,27,98,66},
				   {88,36,68,87,57,62,20,72,03,46,33,67,46,55,12,32,63,93,53,69},
				   {04,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36},
				   {20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,04,36,16},
				   {20,73,35,29,78,31,90,01,74,31,49,71,48,86,81,16,23,57,05,54},
				   {01,70,54,71,83,51,54,69,16,92,33,48,61,43,52,01,89,19,67,48}

																				};
  int diaRightStart = 0;
  int diaLeftStart = 0;
  int hor = 0;
  int vert = 0;
  int cols = 20;
  int rows = 20;

	//calculate greatest vertical product
  for(int i=0; i<cols; i++){
	  for(int j=0; j<rows-4; j++){
		  if(board[i][j]*board[i][j+1]*board[i][j+2]*board[i][j+3] > vert) {
			  vert = board[i][j]*board[i][j+1]*board[i][j+2]*board[i][j+3];
		  }
	  }
  }
  System.out.println(vert);

  //calculate greatest horizontal product
  for(int k=0; k<cols-4; k++){
	  for(int p=0; p<rows; p++){
		  if(board[k][p]*board[k+1][p]*board[k+2][p]*board[k+3][p]> hor){
			  hor = board[k][p]*board[k+1][p]*board[k+2][p]*board[k+3][p];
		  }
	  }
  }
  System.out.println(hor);

  //calculate the greatest diagonal value from left to right
  for(int u=0; u<cols-4; u++){
  	  for(int q=0; q<rows-4;q++){
		  if(board[u][q]*board[u+1][q+1]*board[u+2][q+2]*board[u+3][q+3] > diaLeftStart){
			  diaLeftStart = board[u][q]*board[u+1][q+1]*board[u+2][q+2]*board[u+3][q+3];
		  }
	  }
  }
  System.out.println(diaLeftStart);

  //calculate the greatest diagonal value from right to left
  for(int s=4; s<cols; s++){
    	  for(int d=0; d<rows-4;d++){
  		  if(board[s][d]*board[s-1][d+1]*board[s-2][d+2]*board[s-3][d+3] > diaRightStart){
  			  diaRightStart = board[s][d]*board[s-1][d+1]*board[s-2][d+2]*board[s-3][d+3];
  		  }
  	  }
    }
  System.out.println(diaRightStart);
  }

}