kageru/advent-of-code
1
0
Fork 0
Code Issues 1 Pull Requests Releases Wiki Activity

Remove hardcoded neighbors implementation 

Not that this one is much better, but after hours of trying,
it’s all I got to compile. :(
This commit is contained in:
kageru 2021-07-08 22:17:14 +02:00
parent 4b4f4fbf80
commit a570cf6fda
Signed by: kageru
GPG Key ID: 8282A2BEA4ADA3D2
2 changed files with 75 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
2020/src/bin/day17.rs
View File

@ -23,14 +23,14 @@ fn parse_input<const DIMS: usize>(raw: &str) -> Grid<DIMS, Cell> {
}
fn count_live_neighbors<const D: usize>(p: &PositionND<D>, grid: &Grid<D, Cell>) -> usize
where [(); grid::num_neighbors(D)]: Sized {
where [(); grid::num_neighbors(D) + 1]: Sized {
IntoIterator::into_iter(p.neighbors())
.filter(|n| grid.get(n) == Cell::Alive)
.count()
}
fn make_step<const D: usize>(input: Grid<D, Cell>) -> Grid<D, Cell>
where [(); grid::num_neighbors(D)]: Sized {
where [(); grid::num_neighbors(D) + 1]: Sized {
let readonly = input.clone();
input
.fields
@ -43,7 +43,7 @@ where [(); grid::num_neighbors(D)]: Sized {
}
fn next_state<const D: usize>(pos: &PositionND<D>, grid: &Grid<D, Cell>) -> Cell
where [(); grid::num_neighbors(D)]: Sized {
where [(); grid::num_neighbors(D) + 1]: Sized {
let cell = grid.get(pos);
match (&cell, count_live_neighbors::<D>(pos, grid)) {
(Cell::Alive, 2..=3) => Cell::Alive,
@ -53,7 +53,7 @@ where [(); grid::num_neighbors(D)]: Sized {
}
fn solve<const D: usize>(parsed: &Grid<D, Cell>, steps: usize) -> usize
where [(); grid::num_neighbors(D)]: Sized {
where [(); grid::num_neighbors(D) + 1]: Sized {
let mut clone = parsed.clone();
for _ in 0..steps {
clone = make_step(clone);

121
2020/src/grid/position.rs
View File

@ -1,6 +1,5 @@
extern crate test;
use super::direction::*;
use itertools::iproduct;
use std::{
convert::TryInto, hash::Hash, ops::{Add, Mul, Sub}
};
@ -54,64 +53,60 @@ impl<const DIMS: usize> PositionND<DIMS> {
PositionND { points }
}
// until I can figure out how to properly do that, here’s a “good enough” solution :^)
pub fn neighbors(&self) -> [PositionND<DIMS>; num_neighbors(DIMS)]
where
[PositionND<DIMS>; num_neighbors(DIMS)]: Sized,
[(); num_neighbors(DIMS)]: Sized,
{
let mut out = [PositionND::zero(); num_neighbors(DIMS)];
match DIMS {
2 => {
for (i, n) in iproduct!((-1..=1), (-1..=1))
.filter(|t| t != &(0, 0))
.map(|(x, y)| PositionND::<DIMS>::from_padded(&[self.points[0] + x, self.points[1] + y]))
.enumerate()
{
out[i] = n;
}
}
3 => {
for (i, n) in iproduct!((-1..=1), (-1..=1), (-1..=1))
.filter(|t| t != &(0, 0, 0))
.map(|(x, y, z)| PositionND::<DIMS>::from_padded(&[self.points[0] + x, self.points[1] + y, self.points[2] + z]))
.enumerate()
{
out[i] = n;
}
}
4 => {
for (i, n) in iproduct!((-1..=1), (-1..=1), (-1..=1), (-1..=1))
.filter(|t| t != &(0, 0, 0, 0))
.map(|(x, y, z, w)| {
PositionND::<DIMS>::from_padded(&[self.points[0] + x, self.points[1] + y, self.points[2] + z, self.points[3] + w])
})
.enumerate()
{
out[i] = n;
}
}
_ => unimplemented!(),
where [PositionND<DIMS>; num_neighbors(DIMS) + 1]: Sized {
let ns = neighbor_vectors::<DIMS>();
let mut out = [*self; num_neighbors(DIMS)];
for (out, dir) in out.iter_mut().zip(IntoIterator::into_iter(ns).filter(|n| n != &[0; DIMS])) {
*out = *out + PositionND::from(dir);
}
out
}
}
// Maybe one day :(
/*
fn neighbors_inner<const D: usize>(existing: [i64; DIMS]) -> [[i64; DIMS]; (DIMS - D).pow(3)] {
let out = [[0; DIMS]; (DIMS - D).pow(3)];
let mut index = 0;
for i in -1..=1 {
existing[D] = i;
// I guess that means no recursion with const generics?
for xs in neighbors_inner(existing.clone()) {
out[index] = xs;
index += 1;
#[macro_export]
macro_rules! dim {
($d: expr) => {{
let mut out = [[0; D]; num_neighbors(D) + 1];
let mut i = 0;
for offset in -1..=1 {
for inner in neighbor_vectors::<$d>() {
out[i][0] = offset;
let mut j = 1;
for e in inner {
out[i][j] = e;
j += 1;
}
i += 1;
}
}
out
}};
}
fn neighbor_vectors<const D: usize>() -> [[i64; D]; num_neighbors(D) + 1]
where
{
// I would love to just call neighbor_vectors::<D-1>(), but it seems to be impossible to get the
// correct constraints for that.
match D {
0 => unreachable!(),
1 => {
let mut out = [[0; D]; num_neighbors(D) + 1];
out[0] = [-1; D];
out[1] = [0; D];
out[2] = [1; D];
out
}
2 => dim!(1),
3 => dim!(2),
4 => dim!(3),
5 => dim!(4),
6 => dim!(5),
7 => dim!(6),
// Adding more causes a stackoverflow. How curious.
_ => unimplemented!(),
}
*/
}
impl<const D: usize> Mul<i64> for PositionND<D> {
@ -233,4 +228,30 @@ mod tests {
]
);
}
#[test]
fn test_neighbor_vectors() {
let n = neighbor_vectors::<2>();
assert_eq!(n, [[-1, -1], [-1, 0], [-1, 1], [0, -1], [0, 0], [0, 1], [1, -1], [1, 0], [1, 1],]);
}
#[bench]
fn bench_neighbor_vectors_2d(b: &mut test::Bencher) {
b.iter(|| test::black_box(neighbor_vectors::<2>()))
}
#[bench]
fn bench_neighbor_vectors_3d(b: &mut test::Bencher) {
b.iter(|| test::black_box(neighbor_vectors::<3>()))
}
#[bench]
fn bench_neighbor_vectors_4d(b: &mut test::Bencher) {
b.iter(|| test::black_box(neighbor_vectors::<4>()))
}
#[bench]
fn bench_neighbor_vectors_5d(b: &mut test::Bencher) {
b.iter(|| test::black_box(neighbor_vectors::<5>()))
}
}