224 lines
7.9 KiB
Python
224 lines
7.9 KiB
Python
import re
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import sys
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from typing import Callable
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import numpy as np
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VOID, EMPTY, WALL = 0, 1, 2
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TILE_FROM_CHAR = {" ": VOID, ".": EMPTY, "#": WALL}
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SCORES = {"E": 0, "S": 1, "W": 2, "N": 3}
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board_map_s, direction_s = sys.stdin.read().split("\n\n")
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# board
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board_lines = board_map_s.splitlines()
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max_line = max(len(line) for line in board_lines)
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board = np.array(
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[
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[TILE_FROM_CHAR[c] for c in row] + [VOID] * (max_line - len(row))
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for row in board_map_s.splitlines()
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]
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)
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directions = [
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int(p1) if p2 else p1 for p1, p2 in re.findall(R"(([0-9])+|L|R)", direction_s)
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]
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# find on each row and column the first and last non-void
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row_first_non_void = np.argmax(board != VOID, axis=1)
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row_last_non_void = board.shape[1] - np.argmax(board[:, ::-1] != VOID, axis=1) - 1
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col_first_non_void = np.argmax(board != VOID, axis=0)
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col_last_non_void = board.shape[0] - np.argmax(board[::-1, :] != VOID, axis=0) - 1
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faces = np.zeros_like(board)
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size = np.gcd(board.shape[0], board.shape[1])
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for row in range(0, board.shape[0], size):
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for col in range(row_first_non_void[row], row_last_non_void[row], size):
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faces[row : row + size, col : col + size] = faces.max() + 1
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SIZE = np.gcd(*board.shape)
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# TODO: deduce this from the actual cube...
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faces_wrap: dict[int, dict[str, Callable[[int, int], tuple[int, int, str]]]]
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if board.shape == (12, 16): # example
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faces_wrap = {
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1: {
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"W": lambda y, x: (4, 4 + y, "S"), # 3N
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"N": lambda y, x: (4, 11 - x, "S"), # 2N
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"E": lambda y, x: (11 - y, 15, "W"), # 6E
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},
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2: {
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"W": lambda y, x: (11, 19 - y, "N"), # 6S
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"N": lambda y, x: (0, 11 - y, "S"), # 1N
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"S": lambda y, x: (11, 11 - x, "N"), # 5S
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},
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3: {
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"N": lambda y, x: (x - 4, 8, "E"), # 1W
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"S": lambda y, x: (15 - x, 8, "E"), # 5W
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},
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4: {"E": lambda y, x: (8, 19 - y, "S")}, # 6N
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5: {
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"W": lambda y, x: (7, 15 - y, "N"), # 3S
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"S": lambda y, x: (7, 11 - x, "N"), # 2S
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},
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6: {
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"N": lambda y, x: (19 - x, 11, "W"), # 4E
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"E": lambda y, x: (11 - y, 11, "W"), # 1E
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"S": lambda y, x: (19 - x, 0, "E"), # 2W
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},
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}
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else:
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faces_wrap = {
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1: {
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"W": lambda y, x: (3 * SIZE - y - 1, 0, "E"), # 4W
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"N": lambda y, x: (2 * SIZE + x, 0, "E"), # 6W
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},
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2: {
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"N": lambda y, x: (4 * SIZE - 1, x - 2 * SIZE, "N"), # 6S
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"E": lambda y, x: (3 * SIZE - y - 1, 2 * SIZE - 1, "W"), # 5E
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"S": lambda y, x: (x - SIZE, 2 * SIZE - 1, "W"), # 3E
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},
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3: {
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"W": lambda y, x: (2 * SIZE, y - SIZE, "S"), # 4N
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"E": lambda y, x: (SIZE - 1, SIZE + y, "N"), # 2S
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},
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4: {
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"W": lambda y, x: (3 * SIZE - y - 1, SIZE, "E"), # 1W
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"N": lambda y, x: (SIZE + x, SIZE, "E"), # 3W
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},
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5: {
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"E": lambda y, x: (3 * SIZE - y - 1, 3 * SIZE - 1, "W"), # 2E
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"S": lambda y, x: (2 * SIZE + x, SIZE - 1, "W"), # 6E
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},
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6: {
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"W": lambda y, x: (0, y - 2 * SIZE, "S"), # 1N
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"E": lambda y, x: (3 * SIZE - 1, y - 2 * SIZE, "N"), # 5S
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"S": lambda y, x: (0, x + 2 * SIZE, "S"), # 2N
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},
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}
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def wrap_part_1(y0: int, x0: int, r0: str) -> tuple[int, int, str]:
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if r0 == "E":
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return y0, row_first_non_void[y0], r0
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elif r0 == "S":
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return col_first_non_void[x0], x0, r0
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elif r0 == "W":
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return y0, row_last_non_void[y0], r0
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elif r0 == "N":
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return col_last_non_void[x0], x0, r0
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assert False
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def wrap_part_2(y0: int, x0: int, r0: str) -> tuple[int, int, str]:
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cube = faces[y0, x0]
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assert r0 in faces_wrap[cube]
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return faces_wrap[cube][r0](y0, x0)
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def run(wrap: Callable[[int, int, str], tuple[int, int, str]]) -> tuple[int, int, str]:
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y0 = 0
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x0 = np.where(board[0] == EMPTY)[0][0]
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r0 = "E"
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for direction in directions:
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if isinstance(direction, int):
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while direction > 0:
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if r0 == "E":
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xi = np.where(board[y0, x0 + 1 : x0 + direction + 1] == WALL)[0]
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if len(xi):
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x0 = x0 + xi[0]
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direction = 0
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elif (
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x0 + direction < board.shape[1]
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and board[y0, x0 + direction] == EMPTY
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):
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x0 = x0 + direction
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direction = 0
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else:
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y0_t, x0_t, r0_t = wrap(y0, x0, r0)
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if board[y0_t, x0_t] == WALL:
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x0 = row_last_non_void[y0]
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direction = 0
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else:
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direction = direction - (row_last_non_void[y0] - x0) - 1
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y0, x0, r0 = y0_t, x0_t, r0_t
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elif r0 == "S":
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yi = np.where(board[y0 + 1 : y0 + direction + 1, x0] == WALL)[0]
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if len(yi):
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y0 = y0 + yi[0]
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direction = 0
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elif (
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y0 + direction < board.shape[0]
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and board[y0 + direction, x0] == EMPTY
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):
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y0 = y0 + direction
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direction = 0
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else:
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y0_t, x0_t, r0_t = wrap(y0, x0, r0)
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if board[y0_t, x0_t] == WALL:
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y0 = col_last_non_void[x0]
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direction = 0
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else:
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direction = direction - (col_last_non_void[x0] - y0) - 1
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y0, x0, r0 = y0_t, x0_t, r0_t
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elif r0 == "W":
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left = max(x0 - direction - 1, 0)
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xi = np.where(board[y0, left:x0] == WALL)[0]
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if len(xi):
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x0 = left + xi[-1] + 1
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direction = 0
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elif x0 - direction >= 0 and board[y0, x0 - direction] == EMPTY:
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x0 = x0 - direction
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direction = 0
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else:
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y0_t, x0_t, r0_t = wrap(y0, x0, r0)
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if board[y0_t, x0_t] == WALL:
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x0 = row_first_non_void[y0]
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direction = 0
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else:
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direction = direction - (x0 - row_first_non_void[y0]) - 1
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y0, x0, r0 = y0_t, x0_t, r0_t
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elif r0 == "N":
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top = max(y0 - direction - 1, 0)
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yi = np.where(board[top:y0, x0] == WALL)[0]
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if len(yi):
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y0 = top + yi[-1] + 1
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direction = 0
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elif y0 - direction >= 0 and board[y0 - direction, x0] == EMPTY:
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y0 = y0 - direction
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direction = 0
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else:
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y0_t, x0_t, r0_t = wrap(y0, x0, r0)
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if board[y0_t, x0_t] == WALL:
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y0 = col_first_non_void[x0]
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direction = 0
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else:
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direction = direction - (y0 - col_first_non_void[x0]) - 1
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y0, x0, r0 = y0_t, x0_t, r0_t
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else:
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r0 = {
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"E": {"L": "N", "R": "S"},
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"N": {"L": "W", "R": "E"},
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"W": {"L": "S", "R": "N"},
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"S": {"L": "E", "R": "W"},
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}[r0][direction]
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return y0, x0, r0
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y1, x1, r1 = run(wrap_part_1)
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answer_1 = 1000 * (1 + y1) + 4 * (1 + x1) + SCORES[r1]
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print(f"answer 1 is {answer_1}")
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y2, x2, r2 = run(wrap_part_2)
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answer_2 = 1000 * (1 + y2) + 4 * (1 + x2) + SCORES[r2]
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print(f"answer 2 is {answer_2}")
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