guestroom

y2021/p21.py

+from functools import lru_cache
+from itertools import product, cycle, count
+
+
+@lru_cache(maxsize=None)
+def play(p1, p2, s1=0, s2=0):
+    if s2 >= 21: return 0, 1
+    w1, w2 = 0, 0
+    for die in d3:
+        pN = (p1 + die) % 10 or 10
+        n2, n1 = play(p2, pN, s2, s1 + pN)
+        w1, w2 = (w1 + n1), (w2 + n2)
+    return w1, w2
+
+
+text = open(0).read()
+d3 = [sum(rolls) for rolls in product(range(1, 4), repeat=3)]
+p1, p2 = [int(ln[-1]) for ln in text.splitlines()]
+
+state = {0: (0, p1), 1: (0, p2)}
+d100 = cycle(range(1,101))
+for i in count():
+    score, pos = state[i % 2]
+    pos = (pos + next(d100) + next(d100) + next(d100)) % 10 or 10
+    state[i % 2] = (score + pos, pos)
+    if score + pos >= 1000:
+        break
+print((i + 1) * 3 * min(state.values())[0])
+
+print(max(play(p1, p2)))