Files
2024-12-15 18:31:24 +01:00

262 lines
8.1 KiB
C

#include <stdio.h>
#include <stdlib.h>
#define MAX_DIMENSION 1024
#define MAX_MOVES 1024*1024
typedef enum tile {
EMPTY,
WALL,
BOX,
ROBOT
} tile_t;
typedef struct object {
tile_t type;
int pos[2];
} object_t;
int can_move(object_t ***map, int rows, int columns, int x, int y, int dir[2]);
void move(object_t ***map, int rows, int columns, int x, int y, int dir[2]);
int main() {
char c;
object_t ***map = calloc(MAX_DIMENSION, sizeof(map[0]));
int rows = 0, columns, i = 0;
map[0] = calloc(MAX_DIMENSION, sizeof(object_t*));
int reading_map = 1;
int (*moves)[2] = calloc(MAX_MOVES, sizeof(moves[0]));
int move_count = 0;
int robot_pos[2];
while ((c = getchar()) != EOF) {
if (reading_map) {
if (i == 0 && c == '\n') {
reading_map = 0;
continue;
}
switch (c) {
case '.':
{
object_t *obj = calloc(1, sizeof(obj[0]));
obj->type = EMPTY;
obj->pos[0] = rows;
obj->pos[1] = i;
map[rows][i] = obj;
object_t *obj2 = calloc(1, sizeof(obj2[0]));
obj2->type = EMPTY;
obj2->pos[0] = rows;
obj2->pos[1] = ++i;
map[rows][i] = obj2;
}
break;
case '#':
{
object_t *obj = calloc(1, sizeof(obj[0]));
obj->type = WALL;
obj->pos[0] = rows;
obj->pos[1] = i;
map[rows][i] = obj;
map[rows][++i] = obj;
}
break;
case 'O':
{
object_t *obj = calloc(1, sizeof(obj[0]));
obj->type = BOX;
obj->pos[0] = rows;
obj->pos[1] = i;
map[rows][i] = obj;
map[rows][++i] = obj;
}
break;
case '@':
{
object_t *obj = calloc(1, sizeof(obj[0]));
obj->type = ROBOT;
obj->pos[0] = rows;
obj->pos[1] = i;
map[rows][i] = obj;
robot_pos[0] = rows;
robot_pos[1] = i;
object_t *obj2 = calloc(1, sizeof(obj2[0]));
obj2->type = EMPTY;
obj2->pos[0] = rows;
obj2->pos[1] = ++i;
map[rows][i] = obj2;
}
break;
}
i++;
if (c != '\n') {
continue;
}
columns = i - 1;
i = 0;
rows++;
map[rows] = calloc(MAX_DIMENSION, sizeof(object_t*));
} else {
switch(c) {
case '>':
moves[move_count][0] = 0;
moves[move_count][1] = 1;
move_count++;
break;
case '<':
moves[move_count][0] = 0;
moves[move_count][1] = -1;
move_count++;
break;
case 'v':
moves[move_count][0] = 1;
moves[move_count][1] = 0;
move_count++;
break;
case '^':
moves[move_count][0] = -1;
moves[move_count][1] = 0;
move_count++;
break;
}
}
}
for (i = 0; i < move_count; i++) {
if (can_move(map, rows, columns, robot_pos[0], robot_pos[1], moves[i])) {
move(map, rows, columns, robot_pos[0], robot_pos[1], moves[i]);
robot_pos[0] += moves[i][0];
robot_pos[1] += moves[i][1];
}
}
int sum = 0;
for (i = 0; i < rows; i++) {
for (int j = 0; j < columns; j++) {
if (map[i][j]->type == BOX && map[i][j]->pos[0] == i && map[i][j]->pos[1] == j) {
sum += 100 * i + j;
}
}
}
for (i = 0; i < rows + 1; i++) {
free(map[i]);
}
free(map);
free(moves);
printf("%i\n", sum);
}
int can_move(object_t ***map, int rows, int columns, int x, int y, int dir[2]) {
// Walls cannot move
if (map[x][y]->type == WALL) {
return 0;
}
// Empty space can be filled
if (map[x][y]->type == EMPTY) {
return 1;
}
// A box/robot can move if the next tile is movable
int next_x = x + dir[0];
int next_y = y + dir[1];
// Cannot move out of the map although it should not be possible to reach this
if (next_x < 0 || next_y < 0 || next_x >= rows || next_y >= columns) {
return 0;
}
object_t *next_object = map[next_x][next_y];
if (next_object->type == WALL) {
return 0;
}
if (next_object->type == BOX) {
int can = 1;
if (map[x][y] != map[next_object->pos[0]][next_object->pos[1]]) {
can &= can_move(map, rows, columns, next_object->pos[0], next_object->pos[1], dir);
}
if (map[x][y] != map[next_object->pos[0]][next_object->pos[1] + 1]) {
can &= can_move(map, rows, columns, next_object->pos[0], next_object->pos[1] + 1, dir);
}
return can;
}
return 1;
}
void move(object_t ***map, int rows, int columns, int x, int y, int dir[2]) {
// Walls cannot move
if (map[x][y]->type == WALL) {
return;
}
// Empty space can be filled
if (map[x][y]->type == EMPTY) {
free(map[x][y]);
return;
}
if (map[x][y]->type == BOX) {
int current_positions[2][2];
int next_positions[2][2];
current_positions[0][0] = map[x][y]->pos[0];
current_positions[0][1] = map[x][y]->pos[1];
current_positions[1][0] = map[x][y]->pos[0];
current_positions[1][1] = map[x][y]->pos[1] + 1;
next_positions[0][0] = current_positions[0][0] + dir[0];
next_positions[0][1] = current_positions[0][1] + dir[1];
next_positions[1][0] = current_positions[1][0] + dir[0];
next_positions[1][1] = current_positions[1][1] + dir[1];
if (map[x][y] != map[next_positions[0][0]][next_positions[0][1]]) {
move(map, rows, columns, next_positions[0][0], next_positions[0][1], dir);
}
if (map[x][y] != map[next_positions[1][0]][next_positions[1][1]]) {
move(map, rows, columns, next_positions[1][0], next_positions[1][1], dir);
}
// Move current
map[x][y]->pos[0] = next_positions[0][0];
map[x][y]->pos[1] = next_positions[0][1];
map[next_positions[0][0]][next_positions[0][1]] = map[x][y];
map[next_positions[1][0]][next_positions[1][1]] = map[x][y];
// Free up positions that were left
for (int i = 0; i < 2; i++) {
int left = 1;
for (int j = 0; j < 2; j++) {
if (next_positions[j][0] == current_positions[i][0] && next_positions[j][1] == current_positions[i][1]) {
left = 0;
break;
}
}
if (left) {
object_t *obj = calloc(1, sizeof(obj[0]));
obj->type = EMPTY;
obj->pos[0] = current_positions[i][0];
obj->pos[1] = current_positions[i][1];
map[obj->pos[0]][obj->pos[1]] = obj;
}
}
return;
}
// Robot is a single unit
int next_x = x + dir[0];
int next_y = y + dir[1];
move(map, rows, columns, next_x, next_y, dir);
map[next_x][next_y] = map[x][y];
object_t *obj = calloc(1, sizeof(obj[0]));
obj->type = EMPTY;
obj->pos[0] = x;
obj->pos[1] = y;
map[obj->pos[0]][obj->pos[1]] = obj;
}