From 837a57982798473f1ae4528ca43ed7060b04c07c Mon Sep 17 00:00:00 2001
From: Matej Focko <mfocko@redhat.com>
Date: Sun, 11 Dec 2022 14:27:03 +0100
Subject: [PATCH] day(11): refactor simulation

Signed-off-by: Matej Focko <mfocko@redhat.com>
---
 src/bin/day11.rs | 87 +++++++++++++++++++++---------------------------
 1 file changed, 38 insertions(+), 49 deletions(-)

diff --git a/src/bin/day11.rs b/src/bin/day11.rs
index b30a770..c96a72c 100644
--- a/src/bin/day11.rs
+++ b/src/bin/day11.rs
@@ -119,7 +119,7 @@ impl FromStr for Monkey {
     }
 }
 
-fn round(monkeys: &mut Input, lcm: usize, div: bool) {
+fn round(monkeys: &mut Input, lcm: usize, modular: bool) {
     let mut q: VecDeque<(usize, usize)> = VecDeque::new();
 
     for i in 0..monkeys.len() {
@@ -127,10 +127,11 @@ fn round(monkeys: &mut Input, lcm: usize, div: bool) {
 
         for j in 0..m.items.len() {
             let mut worry = m.operation.apply(m.items[j]);
-            if div {
+            if modular {
+                worry %= lcm;
+            } else {
                 worry /= 3;
             }
-            worry %= lcm;
 
             q.push_back((m.test.get(worry), worry));
             m.inspections += 1;
@@ -156,6 +157,38 @@ fn euclid(a: usize, b: usize) -> usize {
     a
 }
 
+fn simulate_rounds(input: &Input, rounds: usize, modular: bool) -> Output {
+    let mut monkeys = input.clone();
+
+    let lcm = monkeys
+        .iter()
+        .map(|m| m.test.0)
+        .fold(1, |x, y| (x * y) / euclid(x, y));
+
+    let inspect = vec![
+        1, 20, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 1000,
+    ];
+
+    for r in 0..rounds {
+        round(&mut monkeys, lcm, modular);
+
+        if inspect.contains(&(r + 1)) {
+            debug!(
+                "Monkeys: {:?}",
+                monkeys.iter().map(|m| m.inspections).collect_vec()
+            );
+        }
+    }
+
+    monkeys
+        .iter()
+        .map(|m| m.inspections)
+        // .inspect(|x| debug!("inspections of monkey: {x}"))
+        .sorted_by_key(|&i| Reverse(i))
+        .take(2)
+        .product()
+}
+
 struct Day11;
 impl Solution<Input, Output> for Day11 {
     fn parse_input<P: AsRef<Path>>(pathname: P) -> Input {
@@ -166,55 +199,11 @@ impl Solution<Input, Output> for Day11 {
     }
 
     fn part_1(input: &Input) -> Output {
-        let mut monkeys = input.clone();
-
-        let lcm = monkeys
-            .iter()
-            .map(|m| m.test.0)
-            .fold(1, |x, y| x * y / euclid(x, y));
-
-        for _ in 0..20 {
-            round(&mut monkeys, lcm, true);
-        }
-
-        monkeys
-            .iter()
-            .map(|m| m.inspections)
-            .sorted_by_key(|&i| Reverse(i))
-            .take(2)
-            .product()
+        simulate_rounds(input, 20, false)
     }
 
     fn part_2(input: &Input) -> Output {
-        let mut monkeys = input.clone();
-
-        let lcm = monkeys
-            .iter()
-            .map(|m| m.test.0)
-            .fold(1, |x, y| (x * y) / euclid(x, y));
-
-        let inspect = vec![
-            1, 20, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 1000,
-        ];
-
-        for r in 0..10000 {
-            round(&mut monkeys, lcm, false);
-
-            if inspect.contains(&(r + 1)) {
-                debug!(
-                    "Monkeys: {:?}",
-                    monkeys.iter().map(|m| m.inspections).collect_vec()
-                );
-            }
-        }
-
-        monkeys
-            .iter()
-            .map(|m| m.inspections)
-            // .inspect(|x| debug!("inspections of monkey: {x}"))
-            .sorted_by_key(|&i| Reverse(i))
-            .take(2)
-            .product()
+        simulate_rounds(input, 10000, true)
     }
 }