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Don't use silly hashsets

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Bert Peters
2021-12-13 21:34:48 +01:00
parent ffe8d27469
commit 5c764f6627
1 changed files with 25 additions and 23 deletions
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48
2021/src/day13.rs
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@@ -1,7 +1,7 @@
use std::collections::HashSet;
use std::io::Read; use std::io::Read;
use std::str::FromStr; use std::str::FromStr;
use itertools::Itertools;
use nom::branch::alt; use nom::branch::alt;
use nom::bytes::complete::tag; use nom::bytes::complete::tag;
use nom::error::Error; use nom::error::Error;
@@ -63,8 +63,8 @@ fn parse_fold(input: &str) -> IResult<&str, Fold> {
Ok((input, fold)) Ok((input, fold))
} }
fn read_dots(reader: &mut LineIter<'_>) -> HashSet<Coords> { fn read_dots(reader: &mut LineIter<'_>) -> Vec<Coords> {
let mut dots = HashSet::new(); let mut dots = Vec::new();
while let Some(line) = reader.next() { while let Some(line) = reader.next() {
if line.is_empty() { if line.is_empty() {
@@ -73,13 +73,13 @@ fn read_dots(reader: &mut LineIter<'_>) -> HashSet<Coords> {
let (_, coords) = parse_coordinates(line).unwrap(); let (_, coords) = parse_coordinates(line).unwrap();
dots.insert(coords); dots.push(coords);
} }
dots dots
} }
fn apply_fold(dots: &mut HashSet<Coords>, fold: Fold, to_fold: &mut Vec<Coords>) { fn apply_fold(dots: &mut Vec<Coords>, fold: Fold, to_fold: &mut Vec<Coords>) {
match fold { match fold {
Fold::X(coord) => dots.retain(|&(x, y)| { Fold::X(coord) => dots.retain(|&(x, y)| {
if x < coord { if x < coord {
@@ -99,30 +99,30 @@ fn apply_fold(dots: &mut HashSet<Coords>, fold: Fold, to_fold: &mut Vec<Coords>)
}), }),
} }
dots.extend(to_fold.drain(..)); dots.append(to_fold);
} }
fn print_dots(dots: &HashSet<Coords>) -> String { fn print_dots(dots: &[Coords]) -> String {
let (x, y) = dots let (width, height) = dots.iter().fold((0, 0), |(xc, yc), &(xn, yn)| {
.iter() (xc.max(xn as usize + 1), yc.max(yn as usize + 1))
.fold((0, 0), |(xc, yc), &(xn, yn)| (xc.max(xn), yc.max(yn))); });
let mut buffer = String::with_capacity((x as usize + 1) * y as usize); let mut buffer = vec![b' '; width * height];
for y in 0..=y { for &(x, y) in dots {
for x in 0..=x { buffer[x as usize + width * y as usize] = b'#';
if dots.contains(&(x, y)) {
buffer.push('#');
} else {
buffer.push(' ');
}
}
buffer.push('\n');
} }
buffer.pop(); let mut result = String::with_capacity((width + 1) * height);
buffer for line in buffer.chunks_exact(width) {
result += std::str::from_utf8(line).unwrap();
result.push('\n');
}
result.pop();
result
} }
pub fn part1(input: &mut dyn Read) -> String { pub fn part1(input: &mut dyn Read) -> String {
@@ -133,7 +133,9 @@ pub fn part1(input: &mut dyn Read) -> String {
let fold = reader.next().unwrap().parse().unwrap(); let fold = reader.next().unwrap().parse().unwrap();
apply_fold(&mut dots, fold, &mut Vec::new()); apply_fold(&mut dots, fold, &mut Vec::new());
dots.len().to_string() dots.sort_unstable();
dots.into_iter().unique().count().to_string()
} }
pub fn part2(input: &mut dyn Read) -> String { pub fn part2(input: &mut dyn Read) -> String {