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#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
pub struct Monkey {
items: VecDeque<u64>,
op: Box<dyn Fn(u64) -> u64>,
divisor: u64,
modulo: u64,
test: u64,
if_true: usize,
if_false: usize,
count: u64,
}
impl std::fmt::Debug for Monkey {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("Monkey")
.field("items", &self.items)
.finish()
}
}
impl Monkey {
fn parse(mut it: impl Iterator<Item = String>) -> Monkey {
let line = it.next().unwrap();
let cap = regex_captures!(r"^ Starting items: ([0-9, ]*)$", &line)
.unwrap();
let items = cap[1].split(", ").map(|s| s.parse().unwrap()).collect();
let line = it.next().unwrap();
let cap = regex_captures!(
r"^ Operation: new = old ([+*]) (\d+|old)$",
&line
)
.unwrap();
let op = if &cap[2] == "old" {
match &cap[1] {
"+" => Box::new(move |x| x + x) as Box<dyn Fn(u64) -> u64>,
"*" => Box::new(move |x| x * x),
_ => unreachable!(),
}
} else {
let n: u64 = cap[2].parse().unwrap();
match &cap[1] {
"+" => Box::new(move |x| x + n) as Box<dyn Fn(u64) -> u64>,
"*" => Box::new(move |x| x * n),
_ => unreachable!(),
}
};
let line = it.next().unwrap();
let cap =
regex_captures!(r"^ Test: divisible by (\d+)$", &line).unwrap();
let test = cap[1].parse().unwrap();
let line = it.next().unwrap();
let cap =
regex_captures!(r"^ If true: throw to monkey (\d+)$", &line)
.unwrap();
let if_true = cap[1].parse().unwrap();
let line = it.next().unwrap();
let cap =
regex_captures!(r"^ If false: throw to monkey (\d+)$", &line)
.unwrap();
let if_false = cap[1].parse().unwrap();
assert!(it.next().is_none());
Self {
items,
op,
divisor: 0,
modulo: 0,
test,
if_true,
if_false,
count: 0,
}
}
fn inspect(&mut self) -> Option<(u64, usize)> {
let Some(item) = self.items.pop_front()
else { return None };
self.count += 1;
let item = (self.op)(item);
let item = item / self.divisor;
let item = item % self.modulo;
if item % self.test == 0 {
Some((item, self.if_true))
} else {
Some((item, self.if_false))
}
}
fn catch(&mut self, item: u64) {
self.items.push_back(item);
}
fn set_reduce(&mut self, divisor: u64, modulo: u64) {
self.divisor = divisor;
self.modulo = modulo;
}
}
#[derive(Debug)]
pub struct Monkeys {
monkeys: Vec<Monkey>,
}
impl Monkeys {
fn parse(it: impl Iterator<Item = String>) -> Self {
let mut monkeys = vec![];
let mut it = it.peekable();
while it.peek().is_some() {
let header = it.next().unwrap();
let cap = regex_captures!(r"^Monkey (\d+):$", &header).unwrap();
let monkey_idx: usize = cap[1].parse().unwrap();
assert_eq!(monkey_idx, monkeys.len());
monkeys.push(Monkey::parse(parse::chunk(&mut it)));
}
Self { monkeys }
}
fn round(&mut self) {
for i in 0..self.monkeys.len() {
while let Some((item, to)) = self.monkeys[i].inspect() {
self.monkeys[to].catch(item);
}
}
}
fn monkey_business(&self) -> u64 {
let mut counts: Vec<_> =
self.monkeys.iter().map(|m| m.count).collect();
counts.sort_unstable();
counts[counts.len() - 1] * counts[counts.len() - 2]
}
fn set_reduce(&mut self, divisor: u64) {
let modulo = self.monkeys.iter().map(|m| m.test).product();
for monkey in &mut self.monkeys {
monkey.set_reduce(divisor, modulo);
}
}
}
pub fn parse(fh: File) -> Result<Monkeys> {
Ok(Monkeys::parse(parse::raw_lines(fh)))
}
pub fn part1(mut monkeys: Monkeys) -> Result<u64> {
monkeys.set_reduce(3);
for i in 0..20 {
monkeys.round();
}
Ok(monkeys.monkey_business())
}
pub fn part2(mut monkeys: Monkeys) -> Result<u64> {
monkeys.set_reduce(1);
for i in 0..10_000 {
monkeys.round();
}
Ok(monkeys.monkey_business())
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2022, 11).unwrap()).unwrap()).unwrap(),
51075
);
assert_eq!(
part2(parse(parse::data(2022, 11).unwrap()).unwrap()).unwrap(),
11741456163
);
}
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