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| def parse_input(filename): | |
| with open(filename, 'r') as f: | |
| lines = f.read().strip().split('\n') | |
| # Find empty line that separates map and moves | |
| split_idx = lines.index('') | |
| map_lines = lines[:split_idx] | |
| moves = ''.join(lines[split_idx+1:]).strip() | |
| return map_lines, moves | |
| def find_robot_and_boxes(grid): | |
| robot = None | |
| boxes = set() | |
| for y in range(len(grid)): | |
| for x in range(len(grid[y])): | |
| if grid[y][x] == '@': | |
| robot = (x, y) | |
| elif grid[y][x] == 'O': | |
| boxes.add((x, y)) | |
| return robot, boxes | |
| def find_robot_and_boxes_wide(grid): | |
| robot = None | |
| boxes = set() | |
| for y in range(len(grid)): | |
| for x in range(len(grid[y])-1): | |
| if grid[y][x:x+2] == '[]': | |
| boxes.add((x, y)) | |
| elif grid[y][x] == '@': | |
| robot = (x, y) | |
| return robot, boxes | |
| def move_direction(direction): | |
| if direction == '^': return (0, -1) | |
| if direction == 'v': return (0, 1) | |
| if direction == '<': return (-1, 0) | |
| if direction == '>': return (1, 0) | |
| return (0, 0) | |
| def is_wall(grid, x, y): | |
| return grid[y][x] == '#' | |
| def simulate_move(grid, robot, boxes, dx, dy): | |
| new_x, new_y = robot[0] + dx, robot[1] + dy | |
| # Check if moving into wall | |
| if is_wall(grid, new_x, new_y): | |
| return robot, boxes | |
| # Check if moving into box | |
| if (new_x, new_y) in boxes: | |
| box_new_x, box_new_y = new_x + dx, new_y + dy | |
| # Check if box would move into wall or another box | |
| if is_wall(grid, box_new_x, box_new_y) or (box_new_x, box_new_y) in boxes: | |
| return robot, boxes | |
| # Move box | |
| boxes.remove((new_x, new_y)) | |
| boxes.add((box_new_x, box_new_y)) | |
| return (new_x, new_y), boxes | |
| def simulate_move_wide(grid, robot, boxes, dx, dy): | |
| new_x, new_y = robot[0] + dx, robot[1] + dy | |
| # Check if moving into wall | |
| if is_wall(grid, new_x, new_y): | |
| return robot, boxes | |
| # Check if moving into box | |
| box_pos = None | |
| for box in boxes: | |
| if new_x in (box[0], box[0] + 1) and new_y == box[1]: | |
| box_pos = box | |
| break | |
| if box_pos: | |
| box_new_x, box_new_y = box_pos[0] + dx, box_pos[1] + dy | |
| # Check if box would move into wall or another box | |
| if (is_wall(grid, box_new_x, box_new_y) or | |
| is_wall(grid, box_new_x + 1, box_new_y) or | |
| any(b[0] in (box_new_x, box_new_x + 1) and b[1] == box_new_y for b in boxes if b != box_pos)): | |
| return robot, boxes | |
| # Move box | |
| boxes.remove(box_pos) | |
| boxes.add((box_new_x, box_new_y)) | |
| return (new_x, new_y), boxes | |
| def calculate_gps_sum(boxes, height): | |
| return sum((box[1] + 1) * 100 + (box[0] + 1) for box in boxes) | |
| def calculate_gps_sum_wide(boxes, height): | |
| return sum((box[1] + 1) * 100 + (box[0] + 1) for box in boxes) | |
| def scale_map(map_lines): | |
| scaled = [] | |
| for line in map_lines: | |
| new_line = '' | |
| for c in line: | |
| if c == '#': | |
| new_line += '##' | |
| elif c == 'O': | |
| new_line += '[]' | |
| elif c == '.': | |
| new_line += '..' | |
| elif c == '@': | |
| new_line += '@.' | |
| scaled.append(new_line) | |
| return scaled | |
| def solve_part1(map_lines, moves): | |
| grid = map_lines | |
| robot, boxes = find_robot_and_boxes(grid) | |
| for move in moves: | |
| dx, dy = move_direction(move) | |
| robot, boxes = simulate_move(grid, robot, boxes, dx, dy) | |
| return str(calculate_gps_sum(boxes, len(grid))) | |
| def solve_part2(map_lines, moves): | |
| grid = scale_map(map_lines) | |
| robot, boxes = find_robot_and_boxes_wide(grid) | |
| for move in moves: | |
| dx, dy = move_direction(move) | |
| robot, boxes = simulate_move_wide(grid, robot, boxes, dx, dy) | |
| return str(calculate_gps_sum_wide(boxes, len(grid))) | |
| def main(): | |
| map_lines, moves = parse_input('./input.txt') | |
| # Part 1 | |
| print(solve_part1(map_lines, moves)) | |
| # Part 2 | |
| print(solve_part2(map_lines, moves)) | |
| if __name__ == "__main__": | |
| main() |