Day 21.

21.py

@@ -0,0 +1,63 @@
+from collections import defaultdict
+from itertools import combinations, product
+from math import ceil
+
+weapons = {
+    'dagger': {'cost': 8, 'damage': 4},
+    'shortsword': {'cost': 10, 'damage': 5},
+    'warhammer': {'cost': 25, 'damage': 6},
+    'longsword': {'cost': 40, 'damage': 7},
+    'greataxe': {'cost': 74, 'damage': 8}
+}
+
+armour = {
+    'none': {'cost': 0},
+    'leather': {'cost': 13, 'armour': 1},
+    'chainmail': {'cost': 31, 'armour': 2},
+    'splintmail': {'cost': 53, 'armour': 3},
+    'bandedmail': {'cost': 75, 'armour': 4},
+    'platemail': {'cost': 102, 'armour': 5}
+}
+
+rings = {
+    'none1': {'cost': 0},
+    'none2': {'cost': 0},
+    'damage1': {'cost': 25, 'damage': 1},
+    'damage2': {'cost': 50, 'damage': 2},
+    'damage3': {'cost': 100, 'damage': 3},
+    'defense1': {'cost': 20, 'armour': 1},
+    'defense2': {'cost': 40, 'armour': 2},
+    'defense3': {'cost': 80, 'armour': 3}
+}
+
+boss_stats = {
+    'hp': 104,
+    'damage': 8,
+    'armour': 1
+}
+
+def get_loadouts():
+    return product(weapons.values(), armour.values(), combinations(rings.values(), 2))
+
+def get_stats(loadout):
+    weapon, armour, (ring1, ring2) = loadout
+    stats = defaultdict(int)
+    stats['hp'] = 100
+    for part in (weapon, armour, ring1, ring2):
+        for k, v in part.items():
+            stats[k] += v
+    stats['loadout'] = loadout
+    return stats
+
+def will_win(my_stats, boss_stats):
+    inflicted_dpt = max(1, my_stats['damage'] - boss_stats['armour'])
+    received_dpt = max(1, boss_stats['damage'] - my_stats['armour'])
+    boss_death_turn = ceil(boss_stats['hp'] / inflicted_dpt)
+    my_death_turn = ceil(my_stats['hp'] / received_dpt)
+    return my_death_turn >= boss_death_turn
+
+stats = (s for s in (get_stats(l) for l in get_loadouts()) if will_win(s, boss_stats))
+print(min(stats, key=lambda s: s['cost']))
+
+stats = (s for s in (get_stats(l) for l in get_loadouts()) if not will_win(s, boss_stats))
+print(max(stats, key=lambda s: s['cost']))