day 11 python

day11/input

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+Monkey 0:
+  Starting items: 93, 54, 69, 66, 71
+  Operation: new = old * 3
+  Test: divisible by 7
+    If true: throw to monkey 7
+    If false: throw to monkey 1
+
+Monkey 1:
+  Starting items: 89, 51, 80, 66
+  Operation: new = old * 17
+  Test: divisible by 19
+    If true: throw to monkey 5
+    If false: throw to monkey 7
+
+Monkey 2:
+  Starting items: 90, 92, 63, 91, 96, 63, 64
+  Operation: new = old + 1
+  Test: divisible by 13
+    If true: throw to monkey 4
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 65, 77
+  Operation: new = old + 2
+  Test: divisible by 3
+    If true: throw to monkey 4
+    If false: throw to monkey 6
+
+Monkey 4:
+  Starting items: 76, 68, 94
+  Operation: new = old * old
+  Test: divisible by 2
+    If true: throw to monkey 0
+    If false: throw to monkey 6
+
+Monkey 5:
+  Starting items: 86, 65, 66, 97, 73, 83
+  Operation: new = old + 8
+  Test: divisible by 11
+    If true: throw to monkey 2
+    If false: throw to monkey 3
+
+Monkey 6:
+  Starting items: 78
+  Operation: new = old + 6
+  Test: divisible by 17
+    If true: throw to monkey 0
+    If false: throw to monkey 1
+
+Monkey 7:
+  Starting items: 89, 57, 59, 61, 87, 55, 55, 88
+  Operation: new = old + 7
+  Test: divisible by 5
+    If true: throw to monkey 2
+    If false: throw to monkey 5

day11/sample

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+Monkey 0:
+  Starting items: 79, 98
+  Operation: new = old * 19
+  Test: divisible by 23
+    If true: throw to monkey 2
+    If false: throw to monkey 3
+
+Monkey 1:
+  Starting items: 54, 65, 75, 74
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 2
+    If false: throw to monkey 0
+
+Monkey 2:
+  Starting items: 79, 60, 97
+  Operation: new = old * old
+  Test: divisible by 13
+    If true: throw to monkey 1
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 74
+  Operation: new = old + 3
+  Test: divisible by 17
+    If true: throw to monkey 0
+    If false: throw to monkey 1

day11/sol.py

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+from collections import Counter
+def parse(input):
+    if hasattr(input, 'read'):
+        input = input.read()
+    monkeys = []
+    for chunk in input.split("\n\n"):
+        lines = chunk.strip().split("\n")
+        assert 'Starting' in lines[1]
+        items = [int(x.strip()) for x in lines[1].split(":")[1].split(",")]
+        assert 'Operation' in lines[2]
+        op = eval("lambda old: " + lines[2].split("=")[1])
+        assert 'divisible by' in lines[3]
+        divisor = int(lines[3].split()[-1])
+        assert 'true: throw' in lines[4]
+        assert 'false: throw' in lines[5]
+        target = [
+            int(lines[5].split()[-1]),
+            int(lines[4].split()[-1]),
+        ]
+
+        monkeys.append((items, op, divisor, target))
+    return monkeys
+
+def product(it):
+    t = 1
+    for x in it:
+        t  *= x
+    return t
+
+throws = Counter()
+def play(monkeys):
+    N = product(m[2] for m in monkeys)
+    for i, m in enumerate(monkeys):
+        items, op, divisor, target = m
+        for j, x in enumerate(items):
+            throws[i] += 1
+            old = x
+            x = op(x)
+            #x //= 3
+            x %= N
+            trg = target[x % divisor == 0]
+            #print(f'{old} -> {x}. throwing to {trg}')
+            monkeys[trg][0].append(x)
+        items[:] = []
+    return throws
+
+m = parse(open("input"))
+print(m)
+for _ in range(10000):
+    play(m)
+for i, m in enumerate(m):
+    print(i, m[0])
+a, b = sorted(throws.values())[-2:]
+print(a*b)