def solve(): file = "input.txt" with open(file, 'r') as f: lines = f.readlines() grid = [list(line.strip()) for line in lines[:-2]] moves = lines[-1].strip() def get_robot_pos(grid): for r in range(len(grid)): for c in range(len(grid[0])): if grid[r][c] == '@': return r, c def is_valid(r, c, grid): return 0 <= r < len(grid) and 0 <= c < len(grid[0]) and grid[r][c] != '#' def move(grid, dr, dc): r, c = get_robot_pos(grid) nr, nc = r + dr, c + dc if is_valid(nr, nc, grid): if grid[nr][nc] == 'O': nnr, nnc = nr + dr, nc + dc if is_valid(nnr, nnc, grid) and grid[nnr][nnc] == '.': grid[nnr][nnc] = 'O' grid[nr][nc] = '@' grid[r][c] = '.' elif grid[nr][nc] == '.': grid[nr][nc] = '@' grid[r][c] = '.' return grid for move_char in moves: if move_char == '^': grid = move(grid, -1, 0) elif move_char == 'v': grid = move(grid, 1, 0) elif move_char == '<': grid = move(grid, 0, -1) elif move_char == '>': grid = move(grid, 0, 1) gps_sum = 0 for r in range(len(grid)): for c in range(len(grid[0])): if grid[r][c] == 'O': gps_sum += (r * 100) + c print(str(gps_sum)) # Part 2 grid2 = [list(line.strip()) for line in lines[:-2]] grid2 = [[c * 2 for c in row] for row in grid2] for r in range(len(grid2)): for c in range(len(grid2[0])): if grid2[r][c] == 'O': grid2[r][c] = '[' grid2[r][c+1] = ']' elif grid2[r][c] == '@': grid2[r][c+1] = '.' def move2(grid, dr, dc): r, c = get_robot_pos(grid) nr, nc = r + dr, c + dc if is_valid(nr, nc, grid): if grid[nr][nc] == '[': nnr, nnc = nr + dr, nc + dc if is_valid(nnr, nnc, grid) and grid[nnr][nnc] == '.': if is_valid(nnr, nnc + 1, grid) and grid[nnr][nnc + 1] == '.': grid[nnr][nnc] = '[' grid[nnr][nnc + 1] = ']' grid[nr][nc] = '@' grid[nr][nc + 1] = '.' grid[r][c] = '.' grid[r][c + 1] = '.' elif grid[nr][nc] == '.': grid[nr][nc] = '@' grid[r][c] = '.' if grid[r][c+1] == '.': grid[r][c+1] = '.' return grid for move_char in moves: if move_char == '^': grid2 = move2(grid2, -1, 0) elif move_char == 'v': grid2 = move2(grid2, 1, 0) elif move_char == '<': grid2 = move2(grid2, 0, -1) elif move_char == '>': grid2 = move2(grid2, 0, 1) gps_sum2 = 0 for r in range(len(grid2)): for c in range(len(grid2[0])): if grid2[r][c] == '[': gps_sum2 += (r * 100) + c print(str(gps_sum2)) solve()