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#!/usr/bin/python
from copy import copy
class Entity:
pass
class Item:
pass
class Shop:
pass
# Annoying boilerplate to initialize the shop with the items
# given in the text. This is as compact as I could make it.
def init_shop():
table_weapons = [
"Dagger 8 4 0",
"Shortsword 10 5 0",
"Warhammer 25 6 0",
"Longsword 40 7 0",
"Greataxe 74 8 0"
]
table_armour = [
"Leather 13 0 1",
"Chainmail 31 0 2",
"Splintmail 53 0 3",
"Bandedmail 75 0 4",
"Platemail 102 0 5",
"NONE 0 0 0" # Because it's optional
]
table_rings = [
"Damage+1 25 1 0",
"Damage+2 50 2 0",
"Damage+3 100 3 0",
"Defense+1 20 0 1",
"Defense+2 40 0 2",
"Defense+3 80 0 3",
"NONE 0 0 0" # Because it's optional
]
tables = [
(table_weapons, "weapons"),
(table_armour, "armour"),
(table_rings, "rings")
]
shop = Shop()
shop.weapons = []
shop.armour = []
shop.rings = []
for table, attr in tables:
for row in table:
fields = row.split()
item = Item()
item.name = fields[0]
item.cost = int(fields[1])
item.damage = int(fields[2])
item.armour = int(fields[3])
# Sometimes I love you, Python. But usually I don't.
shop.__dict__[attr].append(item)
return shop
def will_win(player, boss):
turn = 0
while boss.health > 0 and player.health > 0:
# Player's turn to attack
if turn % 2 == 0:
boss.health -= max(1, player.damage - boss.armour)
# Boss' turn to attack
else: # turn % 2 == 1
player.health -= max(1, boss.damage - player.armour)
turn += 1
# Did the player win?
return boss.health <= 0
def solve_partn(partn, player_stats, boss_stats):
shop = init_shop()
min_cost = 666
max_cost = 0
for w in shop.weapons:
for a in shop.armour:
for r1 in shop.rings:
for r2 in shop.rings:
# No more than one of each item
if r1 == r2:
continue
boss = copy( boss_stats)
player = copy(player_stats)
cost = w.cost + a.cost + r1.cost + r2.cost
player.damage += w.damage
player.damage += r1.damage
player.damage += r2.damage
player.armour += a.armour
player.armour += r1.armour
player.armour += r2.armour
# Part 1: find lowest cost where player wins
if will_win(player, boss):
if cost < min_cost:
min_cost = cost
# Part 2: find highest cost where player loses
else:
if cost > max_cost:
max_cost = cost
if partn == 1:
return min_cost
else: # partn == 2
return max_cost
def main():
# Set up player's stats given in puzzle text
player = Entity()
player.health = 100
player.damage = 0
player.armour = 0
# Read boss' stats from input text file
boss = Entity()
with open("input.txt", "r") as f:
lines = f.read().splitlines()
for i in range(len(lines)): # len(lines) = 3
words = lines[i].split()
if i == 0:
boss.health = int(words[-1])
if i == 1:
boss.damage = int(words[-1])
if i == 2:
boss.armour = int(words[-1])
print("Part 1 solution:", solve_partn(1, player, boss)) # 121 for me
print("Part 2 solution:", solve_partn(2, player, boss)) # 201 for me
if __name__ == "__main__":
main()
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