bendns' repos / aoc
heh
Diffstat (limited to 'src/main.rs')
-rw-r--r--src/main.rs102
1 files changed, 53 insertions, 49 deletions
diff --git a/src/main.rs b/src/main.rs
index 99f5ab5..77d01d9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -33,63 +33,67 @@
)]
extern crate test;
pub mod util;
+use atools::CollectArray;
pub use util::prelude::*;
-const SIZE: usize = 140;
-fn two([a, b]: [u8; 2]) -> i64 {
- (a - b'0') as i64 * 10 + (b - b'0') as i64
+const W: i32 = 101;
+const H: i32 = 103;
+#[no_mangle]
+pub fn run(i: &str) -> impl Display {
+ let mut grids = [0; 4];
+ i.行()
+ .map(|x| {
+ let ((px, py), (vx, vy)) = x.μ(' ').mb(|x| x.μ1('=').μκ::<i32>(',').Δ());
+ let x = (px + vx * 100).rem_euclid(W);
+ let y = (py + vy * 100).rem_euclid(H);
+ let w = W / 2;
+ let h = H / 2;
+ if x < w && y < h {
+ grids[0] += 1;
+ } else if x < w && y > h {
+ grids[1] += 1;
+ } else if x > w && y < h {
+ grids[2] += 1;
+ } else if x > w && y > h {
+ grids[3] += 1;
+ }
+ })
+ .Θ();
+ grids.iter().product::<u32>()
}
#[no_mangle]
-pub fn run(i: &str) -> impl Display {
- let mut i = i.as_bytes();
- // let i = i.as_chunks_unchecked::<{ SIZE + 1 }>();
- // let get = |x, y| (x < SIZE && y < SIZE).then(|| i[y][x]);
- let mut sum = 0;
- for _ in 0..340 {
- let a_x = two(util::nail(C! { &i["button a: x+".len()..]}));
- let a_y = two(util::nail(C! { &i["button a: x+55, y+".len()..]}));
- let b_x = two(util::nail(
- C! { &i["button a: x+55, y+jj\nbutton b: x+".len()..]},
- ));
- let b_y = two(util::nail(
- C! { &i["button a: x+55, y+jj\nbutton b: x+44, y+".len()..]},
- ));
- i.skip("button a: x+55, y+jj\nbutton b: x+44, y+jj\nprize: x=".len());
- let p_x: i64 = reading::until(&mut i, b',');
- i.skip_n(" y=");
- let p_y: i64 = reading::until(&mut i, b'\n');
- #[inline]
- fn dmod(a: i64, b: i64) -> (i64, i64) {
- unsafe {
- (
- core::intrinsics::unchecked_div(a, b),
- core::intrinsics::unchecked_rem(a, b),
- )
+pub fn p2(i: &str) -> impl Display {
+ let mut positions = Vec::<((i32, i32), (i32, i32))>::with_capacity(500);
+ const W: i32 = 101;
+ const H: i32 = 103;
+ i.行().for_each(|x| {
+ positions.push(x.μ(' ').mb(|x| x.μ1('=').μκ::<i32>(',').Δ()));
+ });
+ let mut at = HashSet::default();
+ 'up: for n in 0.. {
+ for &((px, py), (vx, vy)) in &positions {
+ let x = (px + vx * n).rem_euclid(W);
+ let y = (py + vy * n).rem_euclid(H);
+ if !at.insert((x, y)) {
+ at.clear();
+ continue 'up;
}
}
- // a_x * α + b_x * β = p_x
- // a_y * α + b_y * β = p_y
- let (β, ok) = dmod(
- a_y * p_x - a_x * p_y, //
- a_y * b_x - a_x * b_y,
- );
- if ok == 0 {
- let α = unsafe {
- core::intrinsics::unchecked_div(
- b_y * p_x - b_x * p_y, //
- a_x * b_y - a_y * b_x,
- )
- };
- sum += 3 * α + β;
- }
-
- if i.is_empty() {
- break;
+ for y in 0..H {
+ for x in 0..W {
+ if at.contains(&(x, y)) {
+ print!("██");
+ } else {
+ print!(" ")
+ }
+ }
+ println!();
}
- i.skip(1);
+ return n;
}
- sum
+
+ unreachable!()
}
fn main() {
@@ -101,7 +105,7 @@ fn main() {
// }
// std::fs::write("src/inp.txt", s);
#[allow(unused_unsafe)]
- println!("{}", unsafe { run(i) });
+ println!("{}", unsafe { p2(i) });
}
#[bench]