Add solution to second part of day 9

diff --git a/9/9b.c b/9/9b.c
new file mode 100644 (file)
index 0000000..5d7b0ae
--- /dev/null
+++ b/9/9b.c
@@ -0,0 +1,114 @@
+
+#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, 0) - *(int *)ft_vec_access(diff_row, 0);
+               ft_vec_insert(cur_row, &tmp, 0);
+               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, 0);
+       ft_vec_free(&diffs, ft_vec_free_naive);
+       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);
+}