add day 6

2024/6/part2.c

@@ -0,0 +1,163 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   part2.c                                            :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: tomoron <tomoron@student.42.fr>            +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/07/17 23:03:36 by tomoron           #+#    #+#             */
+/*   Updated: 2024/12/06 13:04:52 by tomoron          ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "libft/libft.h"
+
+typedef struct s_guard
+{
+	int pos[2];
+	int dir[2];
+} t_guard;
+
+static void find_guard(char **split, t_guard *guard)
+{
+	int x;
+	int y;
+	char c;
+
+	y = 0;
+	while(split[y])
+	{
+		x = 0;
+		while(split[y][x])
+		{
+			c = split[y][x];
+			if(c == '^' || c == '>' || c == 'v' || c == '<')
+			{
+				guard->pos[0] = y;
+				guard->pos[1] = x;
+				guard->dir[0] = (1 * (split[y][x] == 'v')) + (-1 * (split[y][x] == '^'));
+				guard->dir[1] = (1 * (split[y][x] == '>')) + (-1 * (split[y][x] == '<'));
+				return ;
+			}
+			x++;
+		}
+		y++;
+	}
+}
+
+static int is_on_map(char **map, int x, int y)
+{
+	return(y >= 0 && x >= 0 && map[y] && map[y][x]);
+}
+
+static void next_dir(int *dir)
+{
+	if(dir[0] == -1 && dir[1] == 0)
+	{
+		dir[0] = 0;
+		dir[1] = 1;
+	}
+	else if(dir[0] == 0 && dir[1] == 1)
+	{
+		dir[0] = 1;
+		dir[1] = 0;
+	}
+	else if(dir[0] == 1 && dir[1] == 0)
+	{
+		dir[0] = 0;
+		dir[1] = -1;
+	}
+	else if(dir[0] == 0 && dir[1] == -1)
+	{
+		dir[0] = -1;
+		dir[1] = 0;
+	}
+}
+
+static void move(char **map, t_guard *guard)
+{
+	int nx;
+	int ny;
+
+	ny = guard->pos[0] + guard->dir[0];
+	nx = guard->pos[1] + guard->dir[1];
+	if(is_on_map(map, nx, ny) && map[ny][nx] == '#')
+	{
+		next_dir(guard->dir);
+		move(map, guard);
+		return ;
+	}
+	guard->pos[0] = ny;
+	guard->pos[1] = nx;
+}
+
+/*static long int count_char(char **map, char c)
+{
+	int x;
+	int y;
+	long int res;
+
+	res = 0;
+	y = 0;
+	while(map[y])
+	{
+		x = 0;
+		while(map[y][x])
+		{
+			if(map[y][x] == c)
+				res++;
+			x++;
+		}
+		y++;
+	}
+	return(res);
+}*/
+
+int is_loop(char **map, t_guard start, int x, int y)
+{
+	t_guard guard;
+	int i;
+
+	guard = start;
+	i = 0;
+	map[x][y] = '#';
+	while(is_on_map(map, guard.pos[1], guard.pos[0]))
+	{
+		move(map, &guard);
+		if(!memcmp(&guard, &start, sizeof(t_guard)) || i++ > 50000)
+		{
+			map[x][y] = '.';
+			return(1);
+		}
+	}
+	map[x][y] = '.';
+	return(0);
+}
+
+long int resolve_part2(char *input, char **split)
+{
+	(void)input;
+	int x;
+	int y;
+	t_guard guard;
+	long int res;
+
+	find_guard(split, &guard);
+	y = 0;
+	res = 0;
+	while(split[y])
+	{
+		x = 0;
+		while(split[y][x])
+		{
+			if(split[x][y] == '.' && is_loop(split, guard, x, y))
+				res++;
+			x++;
+		}
+		y++;
+	}
+	return(res);
+}