rendered paste body/* * In the 20x20 grid below, four numbers along a diagonal line have been marked * in red. * * 08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08 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 08 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 09 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 09 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 08 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 08 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 * * The product of these numbers is 26x63x78x14 = 1788696. * * What is the greatest product of four numbers in any direction (up, down, * left, right, or diagonally) in the 20x20 grid? */#include <stdio.h>#include <stdlib.h>#define SIZE_X 25#define SIZE_Y 25unsigned max_horizontal(unsigned **matrix, int size_x, int size_y){ int i, j, k; unsigned product; unsigned max = 0; for (i = 0; i < size_x; ++i) { for (j = 0; j < size_y - 4; ++j) { product = 1; for (k = j; k < j + 5; ++k) { product *= matrix[i][k]; } if (product > max) { max = product; } } } return max;}int main(void){ unsigned matrix[SIZE_X][SIZE_Y] = { { 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, 4, 56, 62, 0, 81, 49, 31, 73, 55, 79, 14, 29, 93, 71}, {40, 67, 53, 88, 30, 3, 49, 13, 36, 65, 52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56}, {71, 37, 2, 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, 3, 45, 2, 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, 2, 62, 12, 20, 95, 63}, {94, 39, 63, 8, 40, 91, 66, 49, 94, 21, 24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14}, {88, 34, 89, 63, 72, 21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95}, {78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92, 16, 39, 5, 42, 96}, {35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57, 86, 56, 0, 48, 35, 71, 89, 7, 5, 44}, {44, 37, 44, 60, 21, 58, 51, 54, 17, 58, 19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17}, {77, 4, 89, 55, 40, 4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66}, {88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69, 4, 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, 4, 36, 16, 20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81}, {16, 23, 57, 5, 54, 1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48} }; /*unsigned max = 0;*/ unsigned i, j; unsigned **mm; mm = malloc(sizeof(unsigned *) * SIZE_X); if (mm == NULL) exit(-1); for (i = 0; i < SIZE_X; ++i) { mm[i] = malloc(sizeof(unsigned) * SIZE_Y); if (mm[i] == NULL) exit(-1); } for (i = 0; i < SIZE_X; ++i) { for (j = 0; j < SIZE_Y; ++j) { mm[i][j] = matrix[i][j]; } } printf("%u\n", max_horizontal(mm, SIZE_X, SIZE_Y)); for (i = 0; i < SIZE_X; ++i) free(mm[i]); free(mm); return EXIT_SUCCESS;}