Add day 4 solutions

1 files changed, 51 insertions, 0 deletions

diff --git a/2021/04/puzzles.py b/2021/04/puzzles.py
new file mode 100644
index 0000000..581aef5
--- /dev/null
+++ b/2021/04/puzzles.py
@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+
+board = list[list[int]]
+last: board = [[]] * 5
+
+
+def bingo(board: board) -> bool:
+	global last
+
+	if any(
+		board[0][i] == board[1][i]
+		and board[1][i] == board[2][i]
+		and board[2][i] == board[3][i]
+		and board[3][i] == board[4][i]
+		or len(set(board[i])) == 1
+		for i in range(5)
+	):
+		last = board
+		return True
+
+	return False
+
+
+def main() -> None:
+	boards: list[board] = []
+	with open("input", "r", encoding="utf-8") as f:
+		lines = f.readlines()
+		for i, line in enumerate(lines):
+			if i == 0:
+				draws = list(map(int, line.strip().split(",")))
+			elif line == "\n":
+				boards.append([list(map(int, lines[i + j].strip().split())) for j in range(1, 6)])
+
+	# START PART 1
+	while not any(bingo(b) for b in boards):
+	# END PART 1 START PART 2
+	while len(draws) > 0 and len(boards) > 0:
+	# END PART 2
+		num = draws.pop(0)
+		for i, board in enumerate(boards):
+			for j, row in enumerate(board):
+				boards[i][j] = [-1 if n == num else n for n in row]
+		# START PART 2
+		boards = list(filter(lambda b: not bingo(b), boards))
+		# END PART 2
+
+	print(num * sum(map(lambda x: sum(filter(lambda n: n != -1, x)), last)))
+
+
+if __name__ == "__main__":
+	main()