2022: Day 11

Author: Widdin

2022/11/input.txt

@@ -0,0 +1,55 @@
+Monkey 0:
+  Starting items: 54, 61, 97, 63, 74
+  Operation: new = old * 7
+  Test: divisible by 17
+    If true: throw to monkey 5
+    If false: throw to monkey 3
+
+Monkey 1:
+  Starting items: 61, 70, 97, 64, 99, 83, 52, 87
+  Operation: new = old + 8
+  Test: divisible by 2
+    If true: throw to monkey 7
+    If false: throw to monkey 6
+
+Monkey 2:
+  Starting items: 60, 67, 80, 65
+  Operation: new = old * 13
+  Test: divisible by 5
+    If true: throw to monkey 1
+    If false: throw to monkey 6
+
+Monkey 3:
+  Starting items: 61, 70, 76, 69, 82, 56
+  Operation: new = old + 7
+  Test: divisible by 3
+    If true: throw to monkey 5
+    If false: throw to monkey 2
+
+Monkey 4:
+  Starting items: 79, 98
+  Operation: new = old + 2
+  Test: divisible by 7
+    If true: throw to monkey 0
+    If false: throw to monkey 3
+
+Monkey 5:
+  Starting items: 72, 79, 55
+  Operation: new = old + 1
+  Test: divisible by 13
+    If true: throw to monkey 2
+    If false: throw to monkey 1
+
+Monkey 6:
+  Starting items: 63
+  Operation: new = old + 4
+  Test: divisible by 19
+    If true: throw to monkey 7
+    If false: throw to monkey 4
+
+Monkey 7:
+  Starting items: 72, 51, 93, 63, 80, 86, 81
+  Operation: new = old * old
+  Test: divisible by 11
+    If true: throw to monkey 0
+    If false: throw to monkey 4

2022/11/main.py

@@ -0,0 +1,88 @@
+from math import prod, ceil
+
+
+class Monkey:
+    def __init__(self) -> None:
+        self.id = 0
+        self.items = []
+        self.operation = ""
+        self.test = {}
+        self.inspected = 0
+
+    def get_first_item(self) -> int:
+        self.inspected += 1
+        return self.items.pop(0)
+
+
+class Day11:
+
+    def part_one(self) -> int:
+        puzzle_input, _ = self.load_input()
+        return self.get_most_active(monkeys=puzzle_input, rounds=20)
+
+    def part_two(self) -> int:
+        puzzle_input, LCM = self.load_input()
+        return self.get_most_active(monkeys=puzzle_input, rounds=10000, least_common_multiple=LCM)
+
+    def get_most_active(self, monkeys: list, rounds: int, least_common_multiple: int = None) -> int:
+        for _ in range(rounds):
+            for monkey in monkeys:
+                for _ in range(len(monkey.items)):
+                    item = monkey.get_first_item()
+
+                    right = monkey.operation.split()[-1]
+                    left = monkey.operation.split()[-3]
+                    operator = monkey.operation.split()[-2]
+
+                    operators = {'+': lambda x, y: x + y,
+                                 '-': lambda x, y: x - y,
+                                 '*': lambda x, y: x * y}
+
+                    right = item if right == 'old' else int(right)
+                    left = item if left == 'old' else int(left)
+
+                    item = operators[operator](right, left)
+
+                    if least_common_multiple:
+                        item = item % least_common_multiple
+                    else:
+                        item //= 3
+
+                    throw_to = item % monkey.test['divisible'] == 0
+                    monkeys[monkey.test[throw_to]].items.append(item)
+
+        inspected = sorted([monkey.inspected for monkey in monkeys])
+
+        return inspected[-1] * inspected[-2]
+
+    @staticmethod
+    def load_input() -> tuple[list, int]:
+        monkeys, divisibles = [], []
+        with open("input.txt") as file:
+            lines = file.read().splitlines()
+            num_monkeys = ceil(len(lines)/7)
+            for i in range(0, num_monkeys):
+                row_start = i * 7
+                rows = lines[row_start:row_start + 7]
+
+                monkey = Monkey()
+                monkey.id = rows[0].replace(":", "").split()[-1]
+
+                starting_items = map(int, rows[1].replace(",", "").split(":")[-1].split())
+                monkey.items.extend(starting_items)
+
+                monkey.operation = rows[2].split(":")[-1].strip()
+                monkey.test = {
+                    'divisible': int(rows[3].split()[-1]),
+                    True: int(rows[4].split()[-1]),
+                    False: int(rows[5].split()[-1])
+                }
+                divisibles.append(monkey.test['divisible'])
+                monkeys.append(monkey)
+
+        return monkeys, prod(divisibles)
+
+
+day = Day11()
+print(f'Result part 1: {day.part_one()}')
+print(f'Result part 2: {day.part_two()}')

README.md

@@ -14,6 +14,7 @@ My Python Solutions to [Advent of Code](https://adventofcode.com/)
 |8	  |Treetop Tree House|⭐       |⭐     | [🔗](2022/08/main.py) |
 |9	  |Rope Bridge|⭐       |⭐     | [🔗](2022/09/main.py) |
 |10	  |Cathode-Ray Tube|⭐       |⭐     | [🔗](2022/10/main.py) |
+|11	  |Monkey in the Middle|⭐       |⭐     | [🔗](2022/11/main.py) |
 
 ## [2021](https://adventofcode.com/2021)
 | Day | Name | Part 1  | Part 2 | Code |