2021

toolkit.py

@@ -112,5 +112,5 @@ if __name__ == '__main__':
     builtins.re = re
     rel = re.sub(r'.+(y\d+)/(p\d+).+', r'\1.\2', os.environ['FILE'])
     mod = importlib.import_module(rel)
-    print(getattr(mod, 'ans1', None))
-    print(getattr(mod, 'ans2', None))
+    print('ans1', getattr(mod, 'ans1', None))
+    print('ans2', getattr(mod, 'ans2', None))

y2015/p20.py

@@ -0,0 +1,22 @@
+from collections import defaultdict
+from itertools import count
+
+
+def divisors(N):
+    ds = {1, N}
+    for n in range(2, int(N**0.5) + 1):
+        if N % n == 0:
+            ds.update({n, N // n})
+    return ds
+
+
+lim = int(text)
+ans1, ans2 = None, None
+n = 830_000
+while ans1 is None or ans2 is None:
+    ds = divisors(n)
+    if ans1 is None and sum(ds) > lim // 10:
+        ans1 = n
+    if ans2 is None and sum(d for d in ds if n // d <= 50) > lim // 11:
+        ans2 = n
+    n += 1

y2015/p22.py

@@ -0,0 +1,76 @@
+from collections import namedtuple
+import itertools
+
+
+def play(spell, state):
+    is_win = 0
+    hp, mp, boss_hp, boss_dmg, turns, mp_spent, is_hard = state
+    for turn in (spell, None):
+        # prelude
+        if turn is not None and is_hard:
+            hp -= 1
+            if hp <= 0:
+                is_win = -1
+                break
+        if 'r' in turns[-5:]:
+            mp += 101
+        if 'p' in turns[-6:]:
+            boss_hp -= 3
+            if boss_hp <= 0:
+                is_win = 1
+                break
+        # action
+        if turn == 'm':
+            mp_spent += 53
+            boss_hp -= 4
+        elif turn == 'd':
+            mp_spent += 73
+            boss_hp -= 2
+            hp += 2
+        elif turn == 's':
+            mp_spent += 113
+            if 's' in turns[-5:]:
+                is_win = -1
+                break
+        elif turn == 'p':
+            mp_spent += 173
+            if 'p' in turns[-5:]:
+                is_win = -1
+                break
+        elif turn == 'r':
+            mp_spent += 229
+            if 'r' in turns[-4:]:
+                is_win = -1
+                break
+        elif turn == None:
+            hp -= max(boss_dmg - 7 if 's' in turns[-6:] else boss_dmg, 1)
+        turns += (turn,)
+        # denouement
+        if mp_spent > mp:
+            is_win = -1
+            break
+        if boss_hp <= 0:
+            is_win = 1
+            break
+        if hp <= 0:
+            is_win = -1
+            break
+    return is_win, State(hp, mp, boss_hp, boss_dmg, turns, mp_spent, is_hard)
+
+
+State = namedtuple('State', 'hp,mp,boss_hp,boss_dmg,turns,mp_spent,is_hard')
+boss_hp, boss_dmg = map(int, re.findall(r'\d+', text))
+
+pending, wins = [State(50, 500, boss_hp, boss_dmg, tuple(), 0, False)], set()
+while not wins:
+    outcomes = [play(spell, state) for state in pending for spell in 'mdspr']
+    wins |= {state for is_win, state in outcomes if is_win == 1}
+    pending = [state for is_win, state in outcomes if is_win == 0]
+ans1 = min(win.mp_spent for win in wins)
+
+pending, wins = [State(50, 500, boss_hp, boss_dmg, tuple(), 0, True)], set()
+while not wins:
+    outcomes = [play(spell, state) for state in pending for spell in 'mdspr']
+    wins |= {state for is_win, state in outcomes if is_win == 1}
+    pending = [state for is_win, state in outcomes if is_win == 0]
+ans2 = min(win.mp_spent for win in wins)

y2021/p01.py

@@ -0,0 +1,3 @@
+ns = [int(n) for n in text.splitlines()]
+ans1 = sum(b > a for a, b in zip(ns, ns[1:]))
+ans2 = sum(sum(w[:-1]) < sum(w[1:]) for w in zip(ns, ns[1:], ns[2:], ns[3:]))