80 lines
2.6 KiB
Python
80 lines
2.6 KiB
Python
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# get input
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with open("input.txt") as f:
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lines = f.read().split('\n\n')
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raw_numbers = lines[0]
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raw_boards = lines[1:]
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# define a structure for our bingo game
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class Board:
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def __init__(self, points):
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self.unmarked = set()
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self.marked = set()
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for point in points:
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self.unmarked.add(point) # all points are unmarked at start of game
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def __repr__(self):
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return f"\nmarked = {self.marked}\nunmarked = {sorted(self.unmarked)}\n"
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def is_bingo(self):
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# we need to count rows and columns (diagonals don't count)
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i_vals = []
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j_vals = []
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for point in self.marked:
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i, j, _ = point
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i_vals.append(i)
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j_vals.append(j)
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from collections import Counter
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i_count = Counter(i_vals)
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j_count = Counter(j_vals)
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# bingo is called if there are 5 in a row or column;
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# luckily, diagonals don't count
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return ( ( 5 in i_count.values() ) or ( 5 in j_count.values() ) )
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def score(self, last_number):
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score = 0
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# "start by finding the sum of all unmarked numbers"
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for point in self.unmarked:
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_, _, value = point
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score += value
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# "then, multiply that sum by the number that was just called"
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score *= last_number
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return score
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# parse input
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numbers = [int(number) for number in raw_numbers.split(',')]
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boards = set()
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for board in raw_boards:
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points = set(
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(i,j,int(value))
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for i, row in enumerate(board.split('\n'))
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for j, value in enumerate(row.split())
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)
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boards.add(Board(points))
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# refactor out common code
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def check_board(board, number):
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for point in board.unmarked: # point by point.
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_, _, value = point
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if value == number: # if there is a match,
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board.unmarked.remove(point) # then it is no longer unmarked
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board.marked.add(point) # and it should be tracked as marked.
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break # we also don't need to continue checking, since numbers are unique.
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# game loop
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def part1(numbers, boards):
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for number in numbers: # call a number
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for board in boards: # then check the boards
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check_board(board, number)
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if board.is_bingo(): # once bingo is called,
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return board.score(number) # we can calculate our score with that last number.
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print(part1(numbers, boards))
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# game loop 2 -- this time we wanna lose
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def part2(numbers, boards):
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for number in numbers: # call a number
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for board in boards.copy(): # then check the boards
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check_board(board, number)
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if len(boards) == 1 and board.is_bingo(): # if this is the last bingo'd board,
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return board.score(number) # then we can calculate our score.
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elif board.is_bingo(): # otherwise we still have more boards to check
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boards.remove(board) # so we just throw it away.
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print(part2(numbers, boards))
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