bendns' repos / aoc
heh
Diffstat
-rw-r--r--Cargo.toml1
-rw-r--r--src/main.rs56
2 files changed, 23 insertions, 34 deletions
diff --git a/Cargo.toml b/Cargo.toml
index c5480b9..df7a539 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2021"
[dependencies]
arrayvec = "0.7.4"
+bit-set = "0.5.3"
itertools = "0.12.0"
memchr = "2.6.4"
[profile.release]
diff --git a/src/main.rs b/src/main.rs
index 7bae4d2..14052dd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -74,30 +74,14 @@ pub fn p2(i: &str) -> usize {
pub fn p1(i: &str) -> usize {
let i = i.as_bytes();
- let mut n = 0;
- let (x, y) = (65u8, 65u8);
- pub fn countg<I: Iterator<Item = (u8, u8, u8)>>(
- start: (u8, u8, u8),
- graph: &mut impl Fn((u8, u8, u8)) -> I,
- sum: &mut usize,
- has: &mut HashSet<(u8, u8, u8)>,
- ) {
- if start.2 == 64 {
- *sum += 1;
- } else {
- graph(start)
- .map(|n| {
- if has.insert(n) {
- countg(n, graph, sum, has);
- }
- })
- .Θ();
- }
- }
- countg(
- (x, y, 0),
- &mut |(x, y, n)| {
- [
+ let mut state = vec![false; i.len() * 2];
+ let mut q = VecDeque::with_capacity(4096);
+ q.push_back((65u8, 65u8));
+ for step in 1..65 {
+ let is_odd = (step - 1) % 2;
+ for _ in 0..q.len() {
+ let (x, y) = q.pop_front().unwrap();
+ for (x, y) in [
Dir::N + (x, y),
Dir::E + (x, y),
Dir::S + (x, y),
@@ -105,19 +89,23 @@ pub fn p1(i: &str) -> usize {
]
.into_iter()
.flatten()
- .filter(|&(x, _)| x < i.len() as u8)
- .filter(|&(_, y)| y < i.len() as u8)
- .filter(|&(x, y)| C! { i[y.nat() * 132 + x.nat()] } != b'#')
- .map(move |(x, y)| (x, y, n + 1))
- },
- &mut n,
- &mut HashSet::new(),
- );
- n
+ .filter(|&(x, _)| x < 131)
+ .filter(|&(_, y)| y < 131)
+ .filter(|&(x, y)| i[x.nat() * 132 + y.nat()] != b'#')
+ {
+ let cache_key = is_odd * i.len() + x.nat() * 132 + y.nat();
+ if !state[cache_key] {
+ state[cache_key] = true;
+ q.push_back((x, y));
+ }
+ }
+ }
+ }
+ state[i.len()..].iter().copied().filter(|&x| x).count()
}
pub fn run(i: &str) -> impl Display {
- p2(i)
+ p1(i)
}
fn main() {