From: Lukáš Jiřiště <gymnazium.jiriste@gmail.com>
Date: Sun, 10 Dec 2023 09:02:15 +0000 (+0100)
Subject: Add solution to first part of day 10
X-Git-Url: https://git.ljiriste.work/?a=commitdiff_plain;h=ce37db97d0308047f2dcb26d47d4e9b54c02ed15;p=AoC_2023.git

Add solution to first part of day 10
---

diff --git a/10/10.c b/10/10.c
new file mode 100644
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);
+}