Add solution to first part of day 10

diff --git a/10/10.c b/10/10.c
new file mode 100644 (file)
index 0000000..b37cae3
--- /dev/null
+++ b/10/10.c
@@ -0,0 +1,162 @@
+
+#include "libft.h"
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+struct s_matrix
+{
+       size_t  rows;
+       size_t  cols;
+       char    *array;
+};
+typedef struct s_matrix        t_matrix;
+
+char   *get_element(t_matrix matrix, size_t i, size_t j)
+{
+       if (i >= matrix.rows || j >= matrix.cols)
+               return (NULL);
+       return (matrix.array + i * matrix.cols + j);
+}
+
+int    fill_matrix_size(t_matrix *matrix, const char *file_name)
+{
+       int             fd;
+       char    c;
+       char    *line;
+
+       matrix->rows = 1;
+       matrix->cols = 0;
+       fd = open(file_name, O_RDONLY);
+       if (fd < 0)
+               return (-1);
+       c = 'a';
+       while (c != '\n' && c != '\0')
+       {
+               read(fd, &c, 1);
+               ++matrix->cols;
+       }
+       --matrix->cols;
+       line = malloc(matrix->cols + 1);
+       while (read(fd, line, matrix->cols + 1))
+               ++matrix->rows;
+       close(fd);
+       free(line);
+       return (0);
+}
+
+t_matrix       read_as_matrix(const char *file_name)
+{
+       int                     fd;
+       t_matrix        matrix;
+       size_t          i;
+       size_t          j;
+       char            *line;
+
+       fill_matrix_size(&matrix, file_name);
+       fd = open(file_name, O_RDONLY);
+       if (fd < 0)
+               return (matrix);
+       matrix.array = malloc(matrix.rows * matrix.cols * sizeof(*matrix.array));
+       if (!matrix.array)
+               return (matrix);
+       line = malloc(matrix.cols + 1);
+       i = 0;
+       while (i < matrix.rows)
+       {
+               read(fd, line, matrix.cols + 1);
+               j = 0;
+               while (j < matrix.cols)
+               {
+                       *get_element(matrix, i, j) = line[j];
+                       ++j;
+               }
+               ++i;
+       }
+       free(line);
+       return (matrix);
+}
+
+int    to_single_on(int bits)
+{
+       size_t  i;
+
+       i = 0;
+       while (bits != 0)
+               bits &= (1 << i++);
+       return (1 << (i - 1));
+}
+
+/* Connected_sides legend
+ *       -2   
+ *        |
+ *        |
+ * -1----- -----1
+ *        |
+ *        |
+ *        2
+ */
+void   next_step(t_matrix sketch, size_t *i, size_t *j)
+{
+       static int      previous = 0;
+       int                     connected_sides;
+       char            *tile;
+       const char      orig = *get_element(sketch, *i, *j);
+
+       connected_sides = 0;
+       tile = get_element(sketch, *i - 1, *j);
+       if (tile && ft_strchr("|F7S", *tile) && ft_strchr("S|LJ", orig))
+               connected_sides += -2;
+       tile = get_element(sketch, *i + 1, *j);
+       if (tile && ft_strchr("|LJS", *tile) && ft_strchr("S|F7", orig))
+               connected_sides += 2;
+       tile = get_element(sketch, *i, *j - 1);
+       if (tile && ft_strchr("-FLS", *tile) && ft_strchr("S-7J", orig))
+               connected_sides += -1;
+       tile = get_element(sketch, *i, *j + 1);
+       if (tile && ft_strchr("-7JS", *tile) && ft_strchr("S-FL", orig))
+               connected_sides += 1;
+       connected_sides += previous;
+       if (previous == 0)
+               connected_sides = to_single_on(connected_sides);
+       *i += connected_sides / 2;
+       *j += connected_sides % 2;
+       previous = connected_sides;
+       return ;
+}
+
+
+int    loop_length(t_matrix sketch)
+{
+       size_t  i;
+       size_t  j;
+       int             result;
+
+       i = 0;
+       j = 0;
+       result = 0;
+       while (*(get_element(sketch, i, j)) != 'S')
+       {
+               ++j;
+               i += j / sketch.cols;
+               j %= sketch.cols;
+       }
+       while ((*(get_element(sketch, i, j)) != 'S') || result == 0)
+       {
+               next_step(sketch, &i, &j);
+               ++result;
+       }
+       return (result);
+}
+
+int    main(int argc, char **argv)
+{
+       t_matrix        sketch;
+
+       if (argc != 2)
+               return (1);
+       sketch = read_as_matrix(argv[1]);
+       ft_printf("The furthrest pipe segment is %i steps from start.\n", loop_length(sketch) / 2);
+       free(sketch.array);
+       return (0);
+}