kageru/advent-of-code
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Optimize 2020/17 further 

This avoids some hashing per step and unneeded copies.
About 10% faster.
This commit is contained in:
kageru 2020-12-17 16:22:26 +01:00
parent d29e481a24
commit b7d6d40394
2 changed files with 11 additions and 6 deletions
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11
2020/src/bin/day17.rs
View File

@ -12,11 +12,12 @@ fn parse_input<P: Position, F: FnMut((usize, usize)) -> P + Copy>(raw: &str, mut
raw.lines()
.enumerate()
.flat_map(move |(y, l)| l.bytes().enumerate().map(move |(x, b)| (pos_gen((x, y)), b.into())))
.filter(|(_, c)| c == &Cell::Alive)
.collect()
}
fn count_live_neighbors<P: Position>(p: &P, grid: &Grid<P, Cell>) -> usize {
p.neighbors().iter().filter(|&n| grid.get(*n) == Cell::Alive).count()
p.neighbors().iter().filter(|&n| grid.get(n) == Cell::Alive).count()
}
fn make_step<P: Position>(input: Grid<P, Cell>) -> Grid<P, Cell> {
@ -24,10 +25,9 @@ fn make_step<P: Position>(input: Grid<P, Cell>) -> Grid<P, Cell> {
input
.fields
.keys()
.filter(|&&p| readonly.get(p) == Cell::Alive)
.flat_map(|p| p.neighbors())
.map(|pos| {
let cell = readonly.get(pos);
let cell = readonly.get(&pos);
let new = match (&cell, count_live_neighbors(&pos, &readonly)) {
(Cell::Alive, 2..=3) => Cell::Alive,
(Cell::Dead, 3) => Cell::Alive,
@ -35,6 +35,7 @@ fn make_step<P: Position>(input: Grid<P, Cell>) -> Grid<P, Cell> {
};
(pos, new)
})
.filter(|(_, c)| c == &Cell::Alive)
.collect()
}
@ -79,14 +80,14 @@ mod tests {
#[bench]
fn bench_3d_parse(b: &mut test::Bencher) {
let raw = read_input();
b.iter(|| assert_eq!(parse_input(black_box(&raw), |(x, y)| Position3D::from((x, y, 0))).fields.len(), 64));
b.iter(|| assert_eq!(parse_input(black_box(&raw), |(x, y)| Position3D::from((x, y, 0))).fields.len(), 43));
}
#[bench]
#[rustfmt::skip]
fn bench_4d_parse(b: &mut test::Bencher) {
let raw = read_input();
b.iter(|| assert_eq!(parse_input(black_box(&raw), |(x, y)| Position4D::from((x, y, 0, 0))).fields.len(), 64));
b.iter(|| assert_eq!(parse_input(black_box(&raw), |(x, y)| Position4D::from((x, y, 0, 0))).fields.len(), 43));
}
#[bench]

6
2020/src/grid.rs
View File

@ -13,10 +13,14 @@ pub struct Grid<P: Position, T: Display + Default> {
}
impl<P: Position, T: Display + Default + Copy> Grid<P, T> {
pub fn get<Pos: Into<P>>(&self, pos: Pos) -> T {
pub fn get_convert<Pos: Into<P>>(&self, pos: Pos) -> T {
self.fields.get(&pos.into()).copied().unwrap_or_else(|| T::default())
}
pub fn get(&self, pos: &P) -> T {
self.fields.get(pos).copied().unwrap_or_else(|| T::default())
}
pub fn insert<Pos: Into<P>>(&mut self, pos: Pos, t: T) {
self.fields.insert(pos.into(), t);
}