From fd1d42cef773e7ce52cb3b5ad5ee16e65966748e Mon Sep 17 00:00:00 2001
From: =?utf8?q?Luk=C3=A1=C5=A1=20Ji=C5=99i=C5=A1t=C4=9B?=
 <gymnazium.jiriste@gmail.com>
Date: Sun, 10 Dec 2023 15:06:35 +0100
Subject: [PATCH] Add solution to first part of day 9

---
 9/9.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 9/9.c

diff --git a/9/9.c b/9/9.c
new file mode 100644
index 0000000..016c247
--- /dev/null
+++ b/9/9.c
@@ -0,0 +1,115 @@
+
+#include "libft.h"
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+
+void	ft_vec_free_naive(void *vec)
+{
+	ft_vec_free(vec, NULL);
+	return ;
+}
+
+int	all_zero(t_vec *seq)
+{
+	size_t	i;
+
+	i = 0;
+	while (i < seq->size)
+	{
+		if (*(int *)ft_vec_access(seq, i) != 0)
+			return (0);
+		++i;
+	}
+	return (1);
+}
+
+void	add_differences(t_vec *diffs)
+{
+	size_t	i;
+	t_vec	*main;
+	t_vec	seq;
+
+	main = (t_vec *)ft_vec_access(diffs, diffs->size - 1);
+	ft_vec_init(&seq, sizeof(int));
+	i = 0;
+	while (i < main->size - 1)
+	{
+		ft_vec_append(&seq, &(int){*(int *)ft_vec_access(main, i + 1) - *(int *)ft_vec_access(main, i)});
+		++i;
+	}
+	ft_vec_append(diffs, &seq);
+	if (!all_zero(&seq))
+		add_differences(diffs);
+	return ;
+}
+
+int	create_prediction(t_vec *diffs)
+{
+	size_t	i;
+	t_vec	*diff_row;
+	t_vec	*cur_row;
+	int		tmp;
+
+	diff_row = (t_vec *)ft_vec_access(diffs, diffs->size - 1);
+	ft_vec_append(diff_row, &(int){0});
+	i = 1;
+	while (i < diffs->size)
+	{
+		cur_row = (t_vec *)ft_vec_access(diffs, diffs->size - (i + 1));
+		tmp = *(int *)ft_vec_access(cur_row, cur_row->size - 1) + *(int *)ft_vec_access(diff_row, diff_row->size - 1);
+		ft_vec_append(cur_row, &tmp);
+		diff_row = cur_row;
+		++i;
+	}
+	return (tmp);
+}
+
+int	predict(const char *history)
+{
+	t_vec	diffs;
+	t_vec	seq;
+	int		res;
+
+	ft_vec_init(&diffs, sizeof(t_vec));
+	ft_vec_init(&seq, sizeof(int));
+	while (*history)
+	{
+		ft_vec_append(&seq, &(int){ft_atoi(history)});
+		while (ft_isdigit(*history) || *history == '-')
+			++history;
+		if (*history)
+			++history;
+	}
+	ft_vec_append(&diffs, &seq);
+	add_differences(&diffs);
+	create_prediction(&diffs);
+	seq = *(t_vec *)ft_vec_access(&diffs, 0);
+	res = *(int *)ft_vec_access(&seq, seq.size - 1);
+	ft_vec_free(&diffs, ft_vec_free_naive);
+	ft_printf("Prediction:%11i\n", res);
+	return (res);
+}
+
+int	main(int argc, char **argv)
+{
+	int		fd;
+	char	*history;
+	long	res;
+
+	if (argc != 2)
+		return (1);
+	fd = open(argv[1], O_RDONLY);
+	if (fd < 0)
+		return (2);
+	history = get_next_line(fd);
+	res = 0;
+	while (history)
+	{
+		res += predict(history);
+		free(history);
+		history = get_next_line(fd);
+	}
+	ft_printf("The resulting sum is %u.\n", res);
+	return (0);
+}
-- 
2.30.2