Day 11

day11/input.txt

@@ -0,0 +1,55 @@
+Monkey 0:
+  Starting items: 71, 56, 50, 73
+  Operation: new = old * 11
+  Test: divisible by 13
+    If true: throw to monkey 1
+    If false: throw to monkey 7
+
+Monkey 1:
+  Starting items: 70, 89, 82
+  Operation: new = old + 1
+  Test: divisible by 7
+    If true: throw to monkey 3
+    If false: throw to monkey 6
+
+Monkey 2:
+  Starting items: 52, 95
+  Operation: new = old * old
+  Test: divisible by 3
+    If true: throw to monkey 5
+    If false: throw to monkey 4
+
+Monkey 3:
+  Starting items: 94, 64, 69, 87, 70
+  Operation: new = old + 2
+  Test: divisible by 19
+    If true: throw to monkey 2
+    If false: throw to monkey 6
+
+Monkey 4:
+  Starting items: 98, 72, 98, 53, 97, 51
+  Operation: new = old + 6
+  Test: divisible by 5
+    If true: throw to monkey 0
+    If false: throw to monkey 5
+
+Monkey 5:
+  Starting items: 79
+  Operation: new = old + 7
+  Test: divisible by 2
+    If true: throw to monkey 7
+    If false: throw to monkey 0
+
+Monkey 6:
+  Starting items: 77, 55, 63, 93, 66, 90, 88, 71
+  Operation: new = old * 7
+  Test: divisible by 11
+    If true: throw to monkey 2
+    If false: throw to monkey 4
+
+Monkey 7:
+  Starting items: 54, 97, 87, 70, 59, 82, 59
+  Operation: new = old + 8
+  Test: divisible by 17
+    If true: throw to monkey 1
+    If false: throw to monkey 3

day11/part1.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+
+lines = (x.strip() for x in open("input.txt"))
+monkeys = []
+
+
+def create_op(op_line):
+    if "old * old" in op_line:
+        return lambda x: x**2
+    val = int(op_line[6:])
+    if "*" in op_line:
+        return lambda x: x*val
+    return lambda x: x+val
+
+
+for line in lines:
+    monkeys.append({
+        "items": [*map(int, next(lines)[16:].split(", "))],
+        "op": create_op(next(lines)[17:]),
+        "div": int(next(lines)[19:]),
+        "if_true": int(next(lines)[25:]),
+        "if_false": int(next(lines)[26:]),
+        "count": 0
+    })
+    next(lines, None)
+
+for _ in range(20):
+    for idx, monkey in enumerate(monkeys):
+        while monkey['items']:
+            monkey['count'] += 1
+            worry = monkey['op'](monkey['items'].pop(0)) // 3
+            monkeys[monkey['if_true' if worry % monkey['div'] == 0 else 'if_false']]['items'].append(worry)
+
+insp = sorted(monkey['count'] for monkey in monkeys)
+print(insp[-2]*insp[-1])

day11/part2.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+from functools import reduce
+
+lines = (x.strip() for x in open("input.txt"))
+monkeys = []
+
+
+def create_op(op_line):
+    if "old * old" in op_line:
+        return lambda x: x**2
+    val = int(op_line[6:])
+    if "*" in op_line:
+        return lambda x: x*val
+    return lambda x: x+val
+
+
+for line in lines:
+    monkeys.append({
+        "items": [*map(int, next(lines)[16:].split(", "))],
+        "op": create_op(next(lines)[17:]),
+        "div": int(next(lines)[19:]),
+        "if_true": int(next(lines)[25:]),
+        "if_false": int(next(lines)[26:]),
+        "count": 0
+    })
+    next(lines, None)
+
+divisor = reduce(lambda x, y: x*y, set(monkey['div'] for monkey in monkeys))
+
+for _ in range(10000):
+    for monkey in monkeys:
+        while monkey['items']:
+            monkey['count'] += 1
+            worry = monkey['op'](monkey['items'].pop(0)) % divisor
+            monkeys[monkey['if_true' if worry % monkey['div'] == 0 else 'if_false']]['items'].append(worry)
+
+insp = sorted(monkey['count'] for monkey in monkeys)
+print(insp[-2]*insp[-1])