Add day 11

src/day11/mod.rs

@@ -0,0 +1,104 @@
+use crate::read;
+use itertools::Itertools;
+
+#[derive(Debug, PartialEq, Eq, Clone, Hash)]
+enum Operation {
+    Multiply(u64),
+    Add(u64),
+    Square,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Hash)]
+struct Monkey {
+    pub items: Vec<u64>,
+    pub operation: Operation,
+    pub test: u64,
+    pub throw_to: [usize; 2],
+    pub inspected: usize,
+}
+
+impl Monkey {
+    pub fn parse(s: &str) -> Self {
+        let (_, items, operation, operand, test, throw_true, throw_false) = sscanf::sscanf!(
+            s,
+            "Monkey {usize}:
+  Starting items: {str}
+  Operation: new = old {str} {str}
+  Test: divisible by {u64}
+    If true: throw to monkey {usize}
+    If false: throw to monkey {usize}"
+        )
+        .unwrap();
+        let items = items.split(", ").map(|i| i.parse().unwrap()).collect_vec();
+        let operation = match operation {
+            "*" => match operand {
+                "old" => Operation::Square,
+                n => Operation::Multiply(n.parse().unwrap()),
+            },
+            "+" => Operation::Add(operand.parse().unwrap()),
+            _ => unreachable!(),
+        };
+        Self {
+            items,
+            operation,
+            test,
+            throw_to: [throw_true, throw_false],
+            inspected: 0,
+        }
+    }
+}
+
+fn simulate(monkeys: &mut Vec<Monkey>, is_part_1: bool) {
+    let test_product: u64 = monkeys.iter().map(|m| m.test).product();
+    let rounds = if is_part_1 { 20 } else { 10_000 };
+    for _ in 0..rounds {
+        for i in 0..monkeys.len() {
+            let items = monkeys[i].items.clone();
+            for mut item in items {
+                item = match monkeys[i].operation {
+                    Operation::Square => item * item,
+                    Operation::Add(n) => item + n,
+                    Operation::Multiply(n) => item * n,
+                };
+                item = if is_part_1 {
+                    item / 3
+                } else {
+                    item % test_product
+                };
+                let other_monkey =
+                    monkeys[i].throw_to[if item % monkeys[i].test == 0 { 0 } else { 1 }];
+                monkeys[other_monkey].items.push(item);
+            }
+            monkeys[i].inspected += monkeys[i].items.len();
+            monkeys[i].items = Vec::new();
+        }
+    }
+}
+
+fn calculate_monkey_business(monkeys: &[Monkey]) -> usize {
+    monkeys
+        .iter()
+        .map(|m| m.inspected)
+        .sorted()
+        .rev()
+        .take(2)
+        .product()
+}
+
+pub fn run() {
+    let input = read("11");
+    let mut monkeys = input.split("\n\n").map(Monkey::parse).collect_vec();
+
+    #[cfg(feature = "part1")]
+    {
+        let monkeys = &mut monkeys.clone();
+        simulate(monkeys, true);
+        println!("Day 11, Part 01: {}", calculate_monkey_business(monkeys));
+    }
+
+    #[cfg(feature = "part2")]
+    {
+        simulate(&mut monkeys, false);
+        println!("Day 11, Part 02: {}", calculate_monkey_business(&monkeys));
+    }
+}

src/main.rs

@@ -11,6 +11,7 @@ mod day07;
 mod day08;
 mod day09;
 mod day10;
+mod day11;
 mod puter;
 
 fn main() {
@@ -46,6 +47,9 @@ fn main() {
     if cfg!(feature = "day10") || (cfg!(feature = "today") && today == 10) {
         day10::run();
     }
+    if cfg!(feature = "day11") || (cfg!(feature = "today") && today == 11) {
+        day11::run();
+    }
     println!("Finished, time taken: {:?}", now.elapsed())
 }