public class Problem011 { final static public long[][] grid = {{ 8,02,22,97,38,15,00,40,00,75,04,05,07,78,52,12,50,77,91, 8}, {49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,04,56,62,00}, {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}} ; public static long productOfLongArray( long[] a ) { long prod = 1 ; for( long x : a ) { prod *= x ; } return prod ; } public static long maxLong( long a, long b ) { if( a > b ) return a ; return b ; } public static long maxRowProduct( long[][] g, int l ) { int i, j ; long max = 0 ; long[] a = new long[l] ; for( i = 0 ; i < g.length ; i++ ) { for( j = 0 ; j < g[i].length ; j++ ) { a[j%l] = g[i][j] ; if( j > (l-2) ) max = maxLong( max, productOfLongArray( a ) ) ; } } return max ; } public static long maxColumnProduct( long[][] g, int l ) { int i, j ; long max = 0 ; long[] a = new long[l] ; for( i = 0 ; i < g[0].length ; i++ ) { for( j = 0 ; j < g.length ; j++ ) { a[j%l] = g[j][i] ; if( j > (l-2) ) max = maxLong( max, productOfLongArray( a ) ) ; } } return max ; } public static long maxDiagRightProduct( long[][] g, int l ) { int i, j ; long max = 0 ; long[] a = new long[l] ; // Traverse along the top row going // diagonally down and to the right for( i = g.length-l ; i >= 0 ; i-- ) { for( j = 0 ; (i+j) < g.length ; j++ ) { a[j%l] = g[i+j][i+j] ; if( j > (l-2) ) max = maxLong( max, productOfLongArray( a ) ) ; } } // Traverse down the left hand side of the array for( j = 1 ; j <= g[0].length-l ; j++ ) { for( i = 0 ; (i+j) < g.length ; i++ ) { a[i%l] = g[i+j][i] ; if( i > (l-2) ) max = maxLong( max, productOfLongArray( a ) ) ; } } return max ; } public static long maxDiagLeftProduct( long[][] g, int l ) { int i, j ; long max = 0 ; long[] a = new long[l] ; // Traverse along the top row // doing diagonally down and to the left for( i = l-1 ; i <= g.length-1 ; i++ ) { for( j = i ; j >= 0 ; j-- ) { a[j%l] = g[i-j][j] ; if( (i-j) > (l-2) ) max = maxLong( max, productOfLongArray( a ) ) ; } } //Traverse down the right hand side of the array for( j = 1 ; j <= g[g.length-1].length-l ; j++ ) { for( i = g.length-1 ; i >= j ; i-- ) { a[i%l] = g[g.length-i+j-1][i] ; if( (g.length-i) > (l-1) ) max = maxLong( max, productOfLongArray( a ) ) ; } } return max ; } public static void main( String args[] ) { long max = 0 ; max = maxRowProduct( grid, 4 ) ; max = maxLong( max, maxColumnProduct( grid, 4 ) ) ; max = maxLong( max, maxDiagRightProduct( grid, 4 ) ) ; max = maxLong( max, maxDiagLeftProduct( grid, 4 ) ) ; System.out.println( "max: " + max ) ; }}