Day 22

day22/part2.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+
+lines = (x.strip() for x in open("input.txt"))
+
+init_stats = [[], []]
+player2 = False
+for line in lines:
+    if line.startswith("Player"):
+        continue
+    elif line == "":
+        player2 = True
+    else:
+        init_stats[1 if player2 else 0].append(int(line))
+
+def play_game(stats):
+    done = set()
+    while all(len(x) > 0 for x in stats):
+        state = (*stats[0], "+", *stats[1])
+        if state in done:
+            return True, state
+        done.add(state)
+        a, b = stats[0].pop(0), stats[1].pop(0)
+        if len(stats[0]) >= a and len(stats[1]) >= b:
+            winner = play_game([stats[0][:a], stats[1][:b]])[0]
+        else:
+            winner = a > b
+        if winner:
+            stats[0].extend((a, b))
+        else:
+            stats[1].extend((b, a))
+    return len(stats[0]) > 0, stats
+
+winner, out_stats = play_game(init_stats)
+
+print(list(map(lambda x: sum(i*v for i, v in zip(x, range(len(x), 0, -1))), out_stats))[0 if winner else 1])