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clippy

This commit is contained in:
kageru 2023-12-14 10:50:44 +01:00
parent 50bd733e55
commit a81b6e6760
1 changed files with 20 additions and 22 deletions
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42
2023/src/bin/day14.rs
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@ -1,8 +1,8 @@
#![feature(test, try_blocks)] #![feature(test, try_blocks)]
extern crate test; extern crate test;
use aoc2023::{boilerplate, common::*}; use aoc2023::{boilerplate, common::*};
use fnv::{FnvHashMap, FnvHasher}; use fnv::FnvHashMap;
use std::{hash::Hasher, mem::transmute}; use std::mem::transmute;
const DAY: usize = 14; const DAY: usize = 14;
type Parsed = Vec<Vec<Tile>>; type Parsed = Vec<Vec<Tile>>;
@ -36,15 +36,15 @@ fn tilt_north(grid: &mut Parsed) {
} }
fn tilt_west(grid: &mut Parsed) { fn tilt_west(grid: &mut Parsed) {
for y in 0..grid.len() { for line in grid.iter_mut() {
for x in 0..grid[y].len() { for x in 0..line.len() {
if grid[y][x] == Tile::Round { if line[x] == Tile::Round {
let mut i = 0; let mut i = 0;
while let Some(Tile::Empty) = try { grid[y][x.checked_sub(i + 1)?] } { while let Some(Tile::Empty) = try { line[x.checked_sub(i + 1)?] } {
i += 1; i += 1;
} }
grid[y][x] = Tile::Empty; line[x] = Tile::Empty;
grid[y][x - i] = Tile::Round; line[x - i] = Tile::Round;
} }
} }
} }
@ -66,15 +66,15 @@ fn tilt_south(grid: &mut Parsed) {
} }
fn tilt_east(grid: &mut Parsed) { fn tilt_east(grid: &mut Parsed) {
for y in 0..grid.len() { for line in grid.iter_mut() {
for x in (0..grid[y].len()).rev() { for x in (0..line.len()).rev() {
if grid[y][x] == Tile::Round { if line[x] == Tile::Round {
let mut i = 0; let mut i = 0;
while let Some(Tile::Empty) = try { grid[y].get(x + i + 1)? } { while let Some(Tile::Empty) = try { line.get(x + i + 1)? } {
i += 1; i += 1;
} }
grid[y][x] = Tile::Empty; line[x] = Tile::Empty;
grid[y][x + i] = Tile::Round; line[x + i] = Tile::Round;
} }
} }
} }
@ -92,15 +92,12 @@ fn part1(parsed: &Parsed) -> usize {
fn part2(parsed: &Parsed) -> usize { fn part2(parsed: &Parsed) -> usize {
let mut grid = parsed.clone(); let mut grid = parsed.clone();
let mut weights = FnvHashMap::default(); let mut grids = FnvHashMap::default();
let mut n = 0; let mut n = 0;
let cycle = loop { let cycle = loop {
let mut hasher = FnvHasher::default(); // I tried not cloning the grid and instead inserting only a grid hash and the weight here,
for l in grid.iter() { // but that’s only ~15% faster and ugly, so we’ll just do it naively here.
hasher.write(unsafe { transmute(l.as_slice()) }); if let Some(old_n) = grids.insert(grid.clone(), n) {
}
let hash = hasher.finish();
if let Some((_, old_n)) = weights.insert(hash, (weight(&grid), n)) {
break n - old_n; break n - old_n;
} }
n += 1; n += 1;
@ -112,7 +109,8 @@ fn part2(parsed: &Parsed) -> usize {
}; };
const REPETITIONS: usize = 1000000000; const REPETITIONS: usize = 1000000000;
let steps = (REPETITIONS - n) % cycle; let steps = (REPETITIONS - n) % cycle;
weights.into_iter().find_map(|(_, (w, n2))| (n2 == n - cycle + steps).then_some(w)).unwrap() let cycle_start = n - cycle;
grids.into_iter().find_map(|(g, n2)| (n2 == cycle_start + steps).then(|| weight(&g))).unwrap()
} }
boilerplate! { boilerplate! {