refactored

2020/22/22_refactored.py

@@ -0,0 +1,73 @@
+def read_file():
+	with open("input_sample.txt") as f:
+		p1, p2 = f.read().split('\n\n')
+	p1 = p1.split('\n')[1:]
+	p2 = p2.split('\n')[1:]
+	p1 = list(map(int, p1))
+	p2 = list(map(int, p2))
+	return p1, p2
+
+def combat(p1,p2):
+	while True:
+		c1 = p1.pop(0)
+		c2 = p2.pop(0)
+		if c1 > c2:
+			p1 += [c1, c2]
+		else:
+			p2 += [c2, c1]
+		if len(p1) == 0:
+			return p2
+		if len(p2) == 0:
+			return p1
+
+def part1():
+	p1, p2 = read_file()
+	winner_deck = combat(p1, p2)
+	score = 0
+	for i, card in enumerate(reversed(winner_deck)):
+		score += (i+1)*card
+	return score
+
+def recursive_combat(p1, p2):
+	seen = set()
+	while True:
+		# does p1 auto-win?
+		state = (tuple(p1), tuple(p2))
+		if state in seen:
+			return 1, p1
+		seen.add(state)
+		# does anyone win by normal rules?
+		if len(p1) == 0:
+			return 2, p2
+			break
+		if len(p2) == 0:
+			return 1, p1
+		# draw cards
+		c1 = p1.pop(0)
+		c2 = p2.pop(0)
+		# should we recurse?
+		if len(p1) >= c1 and len(p2) >= c2: # play recursive round
+			winner, deck = recursive_combat(p1[:c1],p2[:c2]) # copy that many cards
+			if winner == 1:
+				p1 += [c1, c2]
+			else: # winner == 2
+				p2 += [c2, c1]
+		else: # play normal round
+			if c1 > c2:
+				p1 += [c1, c2]
+			else: # c2 > c1
+				p2 += [c2, c1]
+
+def part2():
+	p1, p2 = read_file()
+	winner, winner_deck = recursive_combat(p1, p2)
+	score = 0
+	for i, card in enumerate(reversed(winner_deck)):
+		score += (i+1)*card
+	return score
+
+def main():
+	print(part1(),part2())
+
+if __name__ == "__main__":
+	main()