bendns' repos / aoc
heh
Diffstat (limited to 'src/main.rs')
-rw-r--r--src/main.rs146
1 files changed, 85 insertions, 61 deletions
diff --git a/src/main.rs b/src/main.rs
index fc0638c..d684198 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,78 +16,102 @@
)]
extern crate test;
pub mod util;
-use arrayvec::ArrayVec;
pub use util::prelude::*;
-pub fn hash16(s: &[u8]) -> u16 {
- s.as_ref()
- .iter()
- .fold(0u16, |acc, &x| acc.wrapping_add(x.widen()).wrapping_mul(17))
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Ord, PartialOrd)]
+enum D {
+ N,
+ E,
+ S,
+ W,
}
-pub fn hash(s: impl AsRef<[u8]>) -> u8 {
- s.as_ref()
- .iter()
- .fold(0u8, |acc, &x| acc.wrapping_add(x).wrapping_mul(17))
+macro_rules! sret {
+ ($a:ident -= $b:expr) => {
+ $a = match $a.checked_sub($b) {
+ Some(x) => x,
+ None => break,
+ }
+ };
}
-pub fn p2(i: &str) -> u32 {
- // can be 5
- let mut 品 = [const { ArrayVec::<_, 6>::new_const() }; 256];
- for i in i
- .as_bytes()
- .split(|&b| b == b',')
- .take(4000)
- .inspect(|x| shucks!(if x.len() > 8))
- {
- match i
- .split_once(|&b| b == b'=')
- .map(|x| x.mr(|x| C! { x[0] } - b'0'))
- {
- None => {
- let ι = &i[..i.len() - 1];
- let h = hash16(ι);
- let lh = h + C! { ι[0] }.widen();
- let β = &mut 品[(h as u8).nat()];
- β.retain(|(α, _)| *α != lh);
+pub fn run(i: &str) -> impl Display {
+ use D::*;
+ let mat = i.行().collect::<Box<_>>();
+ let mut e = vec![vec![false; mat.len()]; mat.len()];
+ let mut been = HashSet::new();
+ fn beam(
+ mat: &[&[u8]],
+ (mut x, mut y): (usize, usize),
+ mut d: D,
+ e: &mut [Vec<bool>],
+ been: &mut HashSet<(usize, usize, D)>,
+ ) {
+ println!("new beam!");
+ loop {
+ if y >= mat.len() || x >= mat.len() {
+ break;
}
- Some((ι, κ)) => {
- let h = hash16(ι);
- let lh = h + C! { ι[0] }.widen();
- let bx = &mut 品[(h as u8).nat()];
- if let Some((_, σ)) = bx.iter_mut().find(|(α, _)| *α == lh) {
- *σ = κ;
- } else {
- unsafe { bx.push_unchecked((lh, κ)) };
+ e[y][x] = true;
+ println!("hello {} (going {d:?})", mat[y][x] as char);
+ match (mat[y][x], d) {
+ (b'|', E | W) => {
+ if been.insert((x, y, N)) {
+ println!("splitting |");
+ if let Some(v) = y.checked_sub(1)
+ && been.insert((x, v, N))
+ {
+ beam(mat, (x, v), N, e, been);
+ }
+ d = S;
+ y += 1;
+ } else {
+ println!("beam death: repetition");
+ return;
+ }
+ }
+ (b'-', N | S) => {
+ if been.insert((x, y, N)) {
+ if let Some(v) = x.checked_sub(1) {
+ println!("splitting -");
+ beam(mat, (v, y), W, e, been);
+ }
+ d = E;
+ x += 1;
+ } else {
+ println!("beam death: repetition");
+ return;
+ }
+ }
+ (b'|' | b'.', N) => sret!(y -= 1),
+ (b'-' | b'.', E) => x += 1,
+ (b'|' | b'.', S) => y += 1,
+ (b'-' | b'.', W) => sret!(x -= 1),
+ (b'/', N) | (b'\\', S) => {
+ d = E;
+ x += 1;
+ }
+ (b'/', E) | (b'\\', W) => {
+ d = N;
+ sret!(y -= 1);
+ }
+ (b'/', S) | (b'\\', N) => {
+ d = W;
+ sret!(x -= 1);
}
+ (b'/', W) | (b'\\', E) => {
+ d = S;
+ y += 1;
+ }
+ _ => unreachable!(),
}
}
+ println!("beam death");
}
- 品.into_iter()
- .ι1::<u32>()
- .map(|(bx, i)| {
- bx.iter()
- .map(|(_, x)| *x)
- .ι1::<u32>()
- .map(|(x, j)| x as u32 * j)
- .sum::<u32>()
- * i
- })
- .sum::<u32>()
-}
-
-#[no_mangle]
-pub fn p1(i: &str) -> impl Display {
- i.as_bytes()
- .split(|&x| x == b',')
- .take(4000)
- .inspect(|x| shucks!(if x.len() > 8))
- .map(|x| hash(x) as u32)
- .sum::<u32>()
-}
-
-pub fn run(i: &str) -> impl Display {
- p2(i)
+ beam(&mat, (0, 0), E, &mut e, &mut been);
+ e.iter()
+ .map(|x| x.iter().filter(|x| **x).count())
+ .sum::<usize>()
}
fn main() {