295 lines
6.1 KiB
C
295 lines
6.1 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* part2.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: tomoron <tomoron@student.42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2024/07/17 23:03:36 by tomoron #+# #+# */
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/* Updated: 2024/12/20 15:16:55 by tomoron ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include "libft/libft.h"
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typedef struct s_pos
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{
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int x;
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int y;
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} t_pos;
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typedef struct s_lst
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{
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t_pos pos;
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uint32_t score;
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int dir[2];
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struct s_lst *next;
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} t_lst;
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static void *create_map(char **map, uint8_t fill, int bloc_size)
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{
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int width;
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int height;
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int i;
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void **res;
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height = 0;
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while(map[height])
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height++;
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width = 0;
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while(map[0][width])
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width++;
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res = malloc((height + 1) * sizeof(void *));
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res[height] = 0;
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i = 0;
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while(i < height)
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{
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res[i] = malloc((width + 1) * bloc_size);
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ft_memset(res[i], fill, width * bloc_size);
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((char **)res)[i][width * bloc_size] = 0;
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i++;
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}
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return(res);
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}
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static int get_new_pos(t_lst **lst, char **vis, t_pos *pos, uint32_t *score, int *dir)
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{
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t_lst *cur;
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t_lst *sel;
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t_lst *p_sel;
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t_lst *prev;
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uint32_t min;
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if(!*lst)
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return(0);
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cur = *lst;
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sel = 0;
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p_sel = 0;
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prev = 0;
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min = -1;
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while(cur)
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{
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if(cur->score < min)
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{
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sel = cur;
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p_sel = prev;
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min = cur->score;
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}
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prev = cur;
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cur = cur->next;
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}
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if(*lst && sel == *lst)
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*lst = (*lst)->next;
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if(p_sel)
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p_sel->next = sel->next;
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sel->next = 0;
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*score = sel->score;
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pos->x = sel->pos.x;
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pos->y = sel->pos.y;
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dir[0] = sel->dir[0];
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dir[1] = sel->dir[1];
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free(sel);
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if(vis[pos->y][pos->x])
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return(get_new_pos(lst, vis, pos, score, dir));
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return(1);
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}
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static void add_lst(t_lst **lst, uint32_t score, t_pos pos, int dir[2])
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{
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t_lst *new;
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new = malloc(sizeof(t_lst));
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new->dir[0] = dir[0];
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new->dir[1] = dir[1];
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new->pos.x = pos.x;
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new->pos.y = pos.y;
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new->score = score;
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new->next = *lst;
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*lst = new;
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}
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static int *rotate_dir(int dir[2], int inv, int *res)
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{
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res[0] = 0;
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res[1] = 0;
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if(dir[0])
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res[1] = dir[0];
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if(dir[1])
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res[0] = dir[1];
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if(inv)
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{
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res[0] = -res[0];
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res[1] = -res[1];
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}
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return(res);
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}
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static int is_valid_move(char **map, int y, int x)
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{
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return(x >= 0 && y >= 0 && map[y] && map[y][x] != '#');
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}
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static void free_lst(t_lst *lst)
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{
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t_lst *tmp;
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while(lst)
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{
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tmp = lst->next;
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free(lst);
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lst = tmp;
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}
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}
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static uint32_t dijkstra(char **map, t_pos pos, uint32_t **dists)
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{
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int dir[2];
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int tmp[2];
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char **visited;
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t_lst *lst;
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uint32_t score;
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visited = create_map(map, 0, 1);
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lst = 0;
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add_lst(&lst, 0, pos, (int [2]){0, 1});
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while(get_new_pos(&lst, visited, &pos, &score, dir))
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{
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if(dists[pos.y][pos.x] > score)
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dists[pos.y][pos.x] = score;
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visited[pos.y][pos.x] = 1;
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if(map[pos.y][pos.x] == '#')
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continue;
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if(is_valid_move(map, pos.y + dir[0], pos.x + dir[1]))
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add_lst(&lst, score + 1, (t_pos){pos.x + dir[1], pos.y + dir[0]}, dir);
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rotate_dir(dir, 0, tmp);
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if(is_valid_move(map, pos.y + tmp[0], pos.x + tmp[1]))
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add_lst(&lst, score + 1, (t_pos){pos.x + tmp[1], pos.y + tmp[0]}, tmp);
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rotate_dir(dir, 1, tmp);
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if(is_valid_move(map, pos.y + tmp[0], pos.x + tmp[1]))
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add_lst(&lst, score + 1, (t_pos){pos.x + tmp[1], pos.y + tmp[0]}, tmp);
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}
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ft_free_str_arr(visited);
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return(0);
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}
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static void get_char(char **map, t_pos *pos, char c)
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{
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pos->y = 0;
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while(map[pos->y])
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{
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pos->x = 0;
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while(map[pos->y][pos->x])
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{
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if(map[pos->y][pos->x] == c)
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return;
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pos->x++;
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}
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pos->y++;
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}
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}
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static long int check_around(uint32_t **dists, t_pos pos, int len, int height, int cheat_dist, int cur_dist)
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{
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long int res;
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int x;
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int y;
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res = 0;
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y = -cheat_dist - 1;
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while(y <= cheat_dist)
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{
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x = -cheat_dist - 1;
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while(x <= cheat_dist)
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{
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if((x || y) && pos.x + x >= 0 && pos.y + y >= 0 && pos.x + x < len && pos.y + y < height && abs(x) + abs(y) <= cheat_dist)
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if(dists[pos.y + y][pos.x + x] != (uint32_t)-1)
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if((dists[pos.y + y][pos.x + x] - cur_dist) - (abs(x) + abs(y)) >= 100)
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res++;
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x++;
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}
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y++;
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}
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return(res);
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}
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static void get_next_pos(char **map, uint32_t **dists, t_pos *pos)
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{
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uint32_t min;
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t_pos new;
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min = -1;
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new.x = 0;
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new.y = 0;
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if(pos->x > 0 && dists[pos->y - 1][pos->x] < min)
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{
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min = dists[pos->y - 1][pos->x];
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new.x = pos->x;
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new.y = pos->y - 1;
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}
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if(pos->y > 0 && dists[pos->y][pos->x - 1] < min)
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{
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min = dists[pos->y][pos->x - 1];
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new.x = pos->x - 1;
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new.y = pos->y;
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}
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if(map[pos->y + 1] && dists[pos->y + 1][pos->x] < min)
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{
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min = dists[pos->x][pos->y + 1];
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new.x = pos->x;
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new.y = pos->y + 1;
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}
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if(map[pos->y][pos->x + 1] && dists[pos->y][pos->x + 1] < min)
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{
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min = dists[pos->x + 1][pos->y];
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new.x = pos->x + 1;
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new.y = pos->y;
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}
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pos->x = new.x;
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pos->y = new.y;
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}
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static long int count_cheats(char **map, t_pos pos, uint32_t **dists)
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{
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long int res;
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uint32_t cur_dist;
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int len;
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int height;
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res = 0;
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height = 0;
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len = 0;
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while(map[height])
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height++;
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while(map[0][len])
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len++;
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while(map[pos.y][pos.x] != 'E')
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{
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cur_dist = dists[pos.y][pos.x];
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dists[pos.y][pos.x] = (uint32_t) -1;
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if(cur_dist != (uint32_t)-1)
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res += check_around(dists, pos, len, height, 20, cur_dist);
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get_next_pos(map, dists, &pos);
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}
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return(res);
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}
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long int resolve_part2(char *input, char **split)
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{
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(void)input;
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t_pos strt;
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uint32_t **dists;
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long int res;
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get_char(split, &strt, 'S');
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dists = create_map(split, 255, sizeof(uint32_t));
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dijkstra(split,strt, dists);
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res = count_cheats(split, strt, dists);
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ft_free_str_arr((void *)dists);
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(void)free_lst;
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return(res);
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}
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