advent-of-code/2021/day4.py
Mikaël Capelle a52d077a40 2021 day 6.
2023-12-09 12:36:10 +01:00

46 lines
1.2 KiB
Python

import sys
import numpy as np
lines = sys.stdin.read().splitlines()
numbers = [int(c) for c in lines[0].split(",")]
boards = np.asarray(
[
[[int(c) for c in line.split()] for line in lines[start : start + 5]]
for start in range(2, len(lines), 6)
]
)
# (round, score) for each board (-1 when not found)
winning_rounds: list[tuple[int, int]] = [(-1, -1) for _ in range(len(boards))]
marked = np.zeros_like(boards, dtype=bool)
for round, number in enumerate(numbers):
# mark boards
marked[boards == number] = True
# check each board for winning
for index in range(len(boards)):
if winning_rounds[index][0] > 0:
continue
if np.any(np.all(marked[index], axis=0) | np.all(marked[index], axis=1)):
winning_rounds[index] = (
round,
number * int(np.sum(boards[index][~marked[index]])),
)
# all boards are winning - break
if np.all(marked.all(axis=1) | marked.all(axis=2)):
break
# part 1
(_, score) = min(winning_rounds, key=lambda w: w[0])
print(f"answer 1 is {score}")
# part 2
(_, score) = max(winning_rounds, key=lambda w: w[0])
print(f"answer 2 is {score}")