Files
aoc/2025/9/part2.c
2025-12-10 15:08:47 +01:00

167 lines
3.7 KiB
C

/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* part2.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: tomoron <tomoron@student.42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2024/07/17 23:03:36 by tomoron #+# #+# */
/* Updated: 2025/12/10 15:08:17 by tomoron ### ########.fr */
/* */
/* ************************************************************************** */
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "libft/libft.h"
typedef struct s_cords
{
double x;
double y;
} t_coords;
static t_coords parse_line(char *line)
{
t_coords res;
res.x = atoi(line);
while(ft_isdigit(*line))
line++;
line++;
res.y = atoi(line);
return(res);
}
static int is_point_on_line(t_coords pos, t_coords a, t_coords b)
{
double cross = (pos.x - a.x) * (b.y - a.y) - (pos.y - a.y) * (b.x - a.x);
if(cross != 0)
return(0);
return(pos.x >= fmin(a.x, b.x) && pos.x <= fmax(a.x, b.x) &&
pos.y >= fmin(a.y, b.y) && pos.y <= fmax(a.y, b.y));
}
static int is_point_in_poly(t_coords pos, t_coords *poly, int len)
{
int inside;
int i;
t_coords cur[2];
double intersect;
inside = 0;
i = 0;
while(i < len)
{
cur[0] = poly[i];
cur[1] = poly[(i + 1) % len];
if(is_point_on_line(pos, cur[0], cur[1]))
{
inside = 1;
break;
}
if((cur[0].y > pos.y) != (cur[1].y > pos.y))
{
intersect = ((cur[1].x - cur[0].x) * (pos.y - cur[0].y)) / (cur[1].y - cur[0].y) + cur[0].x;
if(pos.x < intersect)
inside = !inside;
}
i++;
}
return(inside);
}
static int is_line_in_poly(t_coords p1, t_coords p2, t_coords *poly, int len)
{
t_coords from;
t_coords to;
from.x = fmin(p1.x, p2.x);
from.y = fmin(p1.y, p2.y);
to.x = fmax(p1.x, p2.x);
to.y = fmax(p1.y, p2.y);
while(from.x <= to.x && from.y <= to.y)
{
if(!is_point_in_poly(from, poly, len))
{
return(0);
}
if(from.x != to.x)
from.x++;
else
from.y++;
}
return(1);
}
static int is_all_in_poly(t_coords p1, t_coords p2, t_coords *poly, int len)
{
if(!is_line_in_poly(p1,(t_coords){p2.x, p1.y}, poly, len) ||
!is_line_in_poly((t_coords){p2.x, p1.y}, p2, poly, len) ||
!is_line_in_poly(p2, (t_coords){p1.x, p2.y}, poly, len) ||
!is_line_in_poly((t_coords){p1.x, p2.y},p1, poly, len))
return(0);
return(1);
}
static long int get_biggest_area(t_coords *co, int len)
{
int i;
int j;
long int max;
long int tmp;
i = 0;
max = 0;
while(i < len)
{
j = i;
while(++j < len)
{
if(i == j)
continue;
tmp = ((long)fabs(co[i].x - co[j].x) + 1) * ((long)fabs(co[i].y - co[j].y) + 1);
if(tmp <= max)
continue;
if(!is_point_in_poly((t_coords){co[i].x,co[j].y}, co, len) || !is_point_in_poly((t_coords){co[j].x,co[i].y}, co, len))
continue;
if(!is_all_in_poly(co[i], co[j], co, len))
continue;
printf("got %ld for %.0f, %.0f to %.0f, %.0f checking points \n", tmp, co[i].x, co[i].y, co[j].x, co[j].y);
max = tmp;
}
i++;
}
return(max);
}
long int resolve_part2(char *input, char **split)
{
(void)input;
int len;
t_coords *co;
int i;
len = 0;
while(split[len])
len++;
co = malloc(len * sizeof(t_coords));
i = 0;
while(split[i])
{
co[i] = parse_line(split[i]);
i++;
}
return(get_biggest_area(co, len));
}
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