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from collections import defaultdict
from utils import open_day
class Board:
col_hits: list[int]
row_hits: list[int]
has_bingo: bool
nums: dict[int, tuple[int, int]]
def __init__(self, cells: list[list[int]]) -> None:
width: int = len(cells[0])
height: int = len(cells)
self.col_hits = [height] * width
self.row_hits = [width ] * height
self.nums = dict()
for y, row in enumerate(cells):
for x, cell in enumerate(row):
self.nums[cell] = (x, y)
self.has_bingo = False
def call(self, num: int) -> None:
pos: tuple[int, int] | None = self.nums.pop(num, None)
if pos is None: return
x, y = pos
self.col_hits[x] -= 1
self.row_hits[y] -= 1
self.has_bingo = (
self.has_bingo or
not self.col_hits[x] or
not self.row_hits[y]
)
@property
def unmarked_sum(self) -> int:
return sum(self.nums.keys())
@staticmethod
def from_string(s: str) -> 'Board':
return Board([[int(n) for n in l.split()] for l in s.split('\n')])
def solve(nums: list[int], boards: list[Board]) -> tuple[int, int]:
indices: set[int] = { i for i in range(len(boards)) }
nums_indices: defaultdict[set[int]] = defaultdict(set)
i: int
board: Board
for i, board in enumerate(boards):
for n in board.nums:
nums_indices[n].add(i)
wins: list[int] = []
num: int
for num in nums:
i: int
board: Board
winners: set[int] = set()
num_indices: set[int] = nums_indices.get(num)
for i in indices & num_indices:
boards[i].call(num)
if boards[i].has_bingo:
wins.append(num * boards[i].unmarked_sum)
winners.add(i)
indices.difference_update(winners)
return wins[0], wins[-1]
nums: str | list[int]
boards: list[str] | list[Board]
nums, *boards = open_day(4).read().rstrip().split('\n\n')
nums = list(map(int, nums.split(',')))
boards = [Board.from_string(b) for b in boards]
part1, part2 = solve(nums, boards)
print(part1)
print(part2)
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