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c 2024 6 part 2

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This commit is contained in:
Bill Rossi 2024-12-06 08:22:48 -05:00
parent bb3355014f
commit 12f13cc97e
1 changed files with 57 additions and 8 deletions
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65
c/2024/6/guard_gallivant.c
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@ -5,6 +5,8 @@
#include "../../lib/aoc.h"
#define MAX_LOOP_LENGTH 8000
typedef enum Direction { RIGHT, UP, LEFT, DOWN } Direction;
typedef struct Position {
@ -18,6 +20,9 @@ typedef struct Game {
int height;
Position guard;
Direction guard_direction;
Position guard_start;
Direction guard_start_direction;
int positions[10000];
int position_count;
} Game;
@ -61,7 +66,7 @@ void turn_guard(Game *game) {
game->guard_direction = new_direction;
}
void move_guard(Game *game) {
void move_guard(Game *game, bool deface) {
Position target;
target.x = game->guard.x;
target.y = game->guard.y;
@ -82,9 +87,10 @@ void move_guard(Game *game) {
if (position_has_obstacle(game, target)) turn_guard(game);
else {
if (game->map[index_from_position(game, game->guard)] == '.') {
game->map[index_from_position(game, game->guard)] = 'X';
game->position_count++;
int index = index_from_position(game, game->guard);
if (deface && game->map[index] == '.') {
game->map[index] = 'X';
game->positions[game->position_count++] = index;
}
game->guard.x = target.x;
@ -93,9 +99,10 @@ void move_guard(Game *game) {
}
int main() {
char *line;
char *dirty_map = aoc_read_input();
Game game;
game.map = aoc_read_input();
game.map = dirty_map;
game.width = strchr(game.map, '\n') - game.map + 1;
game.height = strlen(game.map) / game.width;
game.position_count = 0;
@ -104,15 +111,57 @@ int main() {
game.map[i] = '.';
game.guard = position_from_index(&game, i);
game.guard_direction = UP;
game.guard_start = game.guard;
game.guard_start_direction = game.guard_direction;
break;
}
}
char *clean_map = malloc(strlen(dirty_map) + 1);
strcpy(clean_map, dirty_map);
Game time_travel_game;
time_travel_game.map = clean_map;
time_travel_game.width = game.width;
time_travel_game.height = game.height;
time_travel_game.position_count = 0;
time_travel_game.guard = game.guard;
time_travel_game.guard_direction = game.guard_direction;
time_travel_game.guard_start = game.guard;
time_travel_game.guard_start_direction = game.guard_direction;
while (guard_inbounds(&game)) {
move_guard(&game);
move_guard(&game, true);
}
printf("Part 1: %d\n", game.position_count);
int loop_count = 0;
for (int i = 0; i < game.position_count; i++) {
time_travel_game.map[game.positions[i]] = '#';
int gsx = time_travel_game.guard_start.x;
int gsy = time_travel_game.guard_start.y;
int gsd = time_travel_game.guard_start_direction;
time_travel_game.guard = time_travel_game.guard_start;
time_travel_game.guard_direction = time_travel_game.guard_start_direction;
int j = 0;
while (guard_inbounds(&time_travel_game)) {
move_guard(&time_travel_game, false);
if (time_travel_game.guard.x == gsx &&
time_travel_game.guard.y == gsy &&
time_travel_game.guard_direction == gsd) {
loop_count++;
break;
}
j++;
if (j % MAX_LOOP_LENGTH == 0) {
gsx = time_travel_game.guard.x;
gsy = time_travel_game.guard.y;
gsd = time_travel_game.guard_direction;
}
}
time_travel_game.map[game.positions[i]] = '.';
}
printf("Part 1: %d\n", game.position_count);
printf("Part 2: %d\n", loop_count);
aoc_free();
return 0;