Day 11 - Monkey in the Middle 🐒

Author: leifgehrmann

.github/workflows/Day-11.yml

@@ -0,0 +1,18 @@
+name: Day-11
+
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - '**11*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Build
+        run: cargo build --release --verbose
+      - name: Run
+        run: time target/release/aoc 11

README.md

@@ -18,6 +18,7 @@ This is primarily a learning experience, and the code may not be following best
 | 8   | Treetop Tree House        | [src/day_08.rs](src/day_08.rs) | [src/day_08.data](src/day_08.data) | `0m0.002s` | [![Day-08](https://github.com/leifgehrmann/advent-of-code-2022/actions/workflows/Day-08.yml/badge.svg?branch=main)](https://github.com/leifgehrmann/advent-of-code-2022/actions/workflows/Day-08.yml?query=branch%3Amain)
 | 9   | Rope Bridge               |  |  |  | 
 | 10  | Cathode-Ray Tube          | [src/day_10.rs](src/day_10.rs) | [src/day_10.data](src/day_10.data) | `0m0.003s` | [![Day-10](https://github.com/leifgehrmann/advent-of-code-2022/actions/workflows/Day-10.yml/badge.svg?branch=main)](https://github.com/leifgehrmann/advent-of-code-2022/actions/workflows/Day-10.yml?query=branch%3Amain)
+| 11  | Monkey in the Middle      | [src/day_11.rs](src/day_11.rs) | [src/day_11.data](src/day_11.data) |  | [![Day-11](https://github.com/leifgehrmann/advent-of-code-2022/actions/workflows/Day-11.yml/badge.svg?branch=main)](https://github.com/leifgehrmann/advent-of-code-2022/actions/workflows/Day-11.yml?query=branch%3Amain)
 
 † _The measured execution time in GitHub Actions_
 

src/day_11.data

@@ -0,0 +1,55 @@
+Monkey 0:
+  Starting items: 96, 60, 68, 91, 83, 57, 85
+  Operation: new = old * 2
+  Test: divisible by 17
+    If true: throw to monkey 2
+    If false: throw to monkey 5
+
+Monkey 1:
+  Starting items: 75, 78, 68, 81, 73, 99
+  Operation: new = old + 3
+  Test: divisible by 13
+    If true: throw to monkey 7
+    If false: throw to monkey 4
+
+Monkey 2:
+  Starting items: 69, 86, 67, 55, 96, 69, 94, 85
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 6
+    If false: throw to monkey 5
+
+Monkey 3:
+  Starting items: 88, 75, 74, 98, 80
+  Operation: new = old + 5
+  Test: divisible by 7
+    If true: throw to monkey 7
+    If false: throw to monkey 1
+
+Monkey 4:
+  Starting items: 82
+  Operation: new = old + 8
+  Test: divisible by 11
+    If true: throw to monkey 0
+    If false: throw to monkey 2
+
+Monkey 5:
+  Starting items: 72, 92, 92
+  Operation: new = old * 5
+  Test: divisible by 3
+    If true: throw to monkey 6
+    If false: throw to monkey 3
+
+Monkey 6:
+  Starting items: 74, 61
+  Operation: new = old * old
+  Test: divisible by 2
+    If true: throw to monkey 3
+    If false: throw to monkey 1
+
+Monkey 7:
+  Starting items: 76, 86, 83, 55
+  Operation: new = old + 4
+  Test: divisible by 5
+    If true: throw to monkey 4
+    If false: throw to monkey 0

src/day_11.rs

@@ -0,0 +1,99 @@
+use crate::input_reader;
+
+#[derive(PartialEq, Eq, Debug)]
+enum Operator {
+    Add,
+    Mul
+}
+
+struct Monkey {
+    starting_items: Vec<i32>,
+    operator: Operator,
+    operand: Option<i32>, // If null, the operand is 'old'.
+    test_divisible: i32,
+    throw_to_monkey_if_true: usize,
+    throw_to_monkey_if_false: usize
+}
+
+fn part1(monkeys: &Vec<Monkey>) {
+    let mut monkey_states: Vec<Vec<i32>> = vec![vec![]; monkeys.len()];
+    let mut monkey_inspections: Vec<i32>  = vec![0; monkeys.len()];
+    // copy starting items into state
+    for m in 0..monkeys.len() {
+        let cloned_state = &mut monkeys[m].starting_items.clone();
+        monkey_states[m].append(cloned_state)
+    }
+    
+    for _ in 0..20 {
+        for m in 0..monkeys.len() {
+            let monkey = &monkeys[m];
+            let monkey_items = monkey_states[m].clone();
+            for item in monkey_items {
+                // Increase monkey inspection.
+                monkey_inspections[m] += 1;
+
+                // Calculate new worry.
+                let mut worry = item.clone();
+                let operand = monkey.operand.unwrap_or(worry);
+                match monkey.operator {
+                    Operator::Add => worry = worry + operand,
+                    Operator::Mul => worry = worry * operand
+                }
+                worry = worry / 3;
+
+                // Throw to monkey.
+                if worry % monkey.test_divisible == 0 {
+                    monkey_states[monkey.throw_to_monkey_if_true].push(worry);
+                } else {
+                    monkey_states[monkey.throw_to_monkey_if_false].push(worry);
+                }
+            }
+
+            monkey_states[m] = vec![]
+        }
+    }
+
+    monkey_inspections.sort();
+    monkey_inspections.reverse();
+    println!("Part 1: {}", monkey_inspections[0] * monkey_inspections[1]);
+}
+
+pub fn run() {
+    let input = input_reader::read_file_in_cwd("src/day_11.data");
+
+    let lines: Vec<&str> = input.split("\n\n").collect();
+    let monkeys: Vec<Monkey> = lines.iter().map(|&val| {
+        let lines: Vec<&str> = val.split("\n").collect();
+        // Parse items
+        let starting_items: Vec<i32> = lines[1]
+            .replace(",", "")
+            .split(" ").skip(4)
+            .map(|i| { i.parse::<i32>().unwrap() }).collect();
+        // Parse operation
+        let operation_str: Vec<&str> = lines[2].split(" ").collect();
+        let operator = match operation_str[6] {
+            "+" => Operator::Add,
+            _ => Operator::Mul
+        };
+        let operand = operation_str[7].parse::<i32>().ok();
+        // Parse test
+        let test_str: Vec<&str> = lines[3].split(" ").collect();
+        let test_divisible = test_str[5].parse::<i32>().unwrap();
+        // Parse throws
+        let throw_true_str: Vec<&str> = lines[4].split(" ").collect();
+        let throw_false_str: Vec<&str> = lines[5].split(" ").collect();
+        let throw_true = throw_true_str[9].parse::<usize>().unwrap();
+        let throw_false = throw_false_str[9].parse::<usize>().unwrap();
+        
+        return Monkey {
+            starting_items,
+            operator,
+            operand, 
+            test_divisible,
+            throw_to_monkey_if_true: throw_true,
+            throw_to_monkey_if_false: throw_false
+        }
+    }).collect();
+
+    part1(&monkeys);
+}

src/main.rs

@@ -9,6 +9,7 @@ mod day_06;
 mod day_08;
 // mod day_09;
 mod day_10;
+mod day_11;
 
 fn main() {
     let day: String = std::env::args().nth(1).expect(
@@ -27,6 +28,7 @@ fn main() {
         "08" => day_08::run(),
         // "09" => day_09::run(),
         "10" => day_10::run(),
+        "11" => day_11::run(),
         _ => println!("No valid day given. Possible options are: 01-25."),
     };
 }