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|
#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
pub enum Condition {
Good,
Bad,
Unknown,
}
impl TryFrom<char> for Condition {
type Error = anyhow::Error;
fn try_from(value: char) -> std::result::Result<Self, Self::Error> {
Ok(match value {
'.' => Condition::Good,
'#' => Condition::Bad,
'?' => Condition::Unknown,
_ => bail!("unknown condition {value}"),
})
}
}
pub struct Record {
condition: Vec<Condition>,
lengths: Vec<usize>,
}
impl Record {
fn arrangements(&self) -> usize {
arrangements(&self.condition, &self.lengths)
}
fn unfold(self) -> Self {
let mut condition = vec![];
condition.extend_from_slice(&self.condition);
for _ in 0..4 {
condition.push(Condition::Unknown);
condition.extend_from_slice(&self.condition);
}
Self {
condition,
lengths: self.lengths.repeat(5),
}
}
}
fn arrangements(conditions: &[Condition], chunks: &[usize]) -> usize {
let mut memo = HashMap::new();
arrangements_memo(conditions, chunks, &mut memo)
}
fn arrangements_memo<'a, 'b>(
conditions: &'a [Condition],
chunks: &'b [usize],
memo: &mut HashMap<(&'a [Condition], &'b [usize]), usize>,
) -> usize {
if let Some(count) = memo.get(&(conditions, chunks)) {
return *count;
}
let count = _arrangements(conditions, chunks, memo);
memo.insert((conditions, chunks), count);
count
}
fn _arrangements<'a, 'b>(
conditions: &'a [Condition],
chunks: &'b [usize],
memo: &mut HashMap<(&'a [Condition], &'b [usize]), usize>,
) -> usize {
let good_prefix = conditions
.iter()
.copied()
.take_while(|condition| *condition == Condition::Good)
.count();
if good_prefix > 0 {
return arrangements_memo(&conditions[good_prefix..], chunks, memo);
}
if conditions.is_empty() {
if chunks.is_empty() {
return 1;
} else {
return 0;
}
} else if chunks.is_empty() {
if conditions.contains(&Condition::Bad) {
return 0;
} else {
return 1;
}
} else if chunks.iter().sum::<usize>() + chunks.len() - 1
> conditions.len()
{
return 0;
}
let next = conditions
.iter()
.copied()
.take_while(|condition| *condition != Condition::Good)
.take(chunks[0])
.count();
if next < chunks[0] {
if conditions
.iter()
.copied()
.take(next)
.all(|condition| condition == Condition::Unknown)
{
return arrangements_memo(&conditions[next..], chunks, memo);
} else {
return 0;
}
}
let mut total = 0;
if conditions[0] == Condition::Unknown {
total += arrangements_memo(&conditions[1..], chunks, memo);
}
if next == conditions.len() || conditions[next] != Condition::Bad {
total += arrangements_memo(
&conditions[(next + 1).min(conditions.len())..],
&chunks[1..],
memo,
);
}
total
}
impl std::str::FromStr for Record {
type Err = anyhow::Error;
fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
let mut parts = s.split_whitespace();
Ok(Record {
condition: parts
.next()
.unwrap()
.chars()
.map(|c| c.try_into().unwrap())
.collect(),
lengths: parts
.next()
.unwrap()
.split(',')
.map(|s| s.parse().unwrap())
.collect(),
})
}
}
pub fn parse(fh: File) -> Result<Vec<Record>> {
Ok(parse::lines(fh).collect())
}
pub fn part1(records: Vec<Record>) -> Result<i64> {
Ok(records
.into_iter()
.map(|record| record.arrangements())
.sum::<usize>()
.try_into()
.unwrap())
}
pub fn part2(records: Vec<Record>) -> Result<i64> {
Ok(records
.into_iter()
.map(|record| record.unfold().arrangements())
.sum::<usize>()
.try_into()
.unwrap())
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2023, 12).unwrap()).unwrap()).unwrap(),
7407
);
assert_eq!(
part2(parse(parse::data(2023, 12).unwrap()).unwrap()).unwrap(),
30568243604962
);
}
|
