2022 day7/rust: cleanup

This commit is contained in:
Xiretza 2022-12-07 19:16:30 +01:00
parent 5d846eb88c
commit a74b1f4bc6

View file

@ -1,76 +1,62 @@
#![warn(clippy::pedantic)] #![warn(clippy::pedantic)]
use std::{ use std::{collections::HashMap, io::stdin, path::PathBuf};
collections::HashMap,
hash::Hash,
io::{stdin, Read},
path::{Path, PathBuf},
};
use aoc::*; use aoc::PathExt;
fn find_dir_to_delete(dirs: &HashMap<PathBuf, usize>) -> usize {
const TOTAL_SPACE: usize = 70_000_000;
const REQUIRED_SPACE: usize = 30_000_000;
let unused = TOTAL_SPACE - dirs[&*PathBuf::from("/")];
let to_free = REQUIRED_SPACE - unused;
let mut sizes: Vec<_> = dirs.values().copied().collect();
sizes.sort_unstable();
match sizes.binary_search(&to_free) {
Ok(i) | Err(i) => sizes[i],
}
}
fn main() { fn main() {
let mut data = String::new();
stdin().read_to_string(&mut data).unwrap();
let mut cwd = PathBuf::new(); let mut cwd = PathBuf::new();
cwd.push("/"); cwd.push("/");
let mut dirs: HashMap<PathBuf, usize> = HashMap::new(); let mut dirs: HashMap<PathBuf, usize> = HashMap::new();
for line in data.lines() { for line in stdin().lines() {
let line = line.unwrap();
if let Some(command) = line.strip_prefix("$ ") { if let Some(command) = line.strip_prefix("$ ") {
let mut args = command.split_whitespace(); let mut args = command.split_whitespace();
let command = args.next().unwrap();
match command { if args.next().unwrap() != "cd" {
"ls" => { continue;
dirs.remove(&cwd); }
match args.next().unwrap() {
".." => assert!(cwd.pop()),
path => {
cwd.push(path);
assert!(!dirs.contains_key(&cwd));
} }
"cd" => {
let dir = args.next().unwrap();
match dir {
".." => assert!(cwd.pop()),
path => cwd.push(path),
}
}
_ => panic!("unknown command {command}"),
} }
} else { } else {
let (size, _name) = line.split_once(' ').unwrap(); let size = line.split_whitespace().next().unwrap();
if size == "dir" { if size == "dir" {
// skip continue;
} else {
let size: usize = size.parse().unwrap();
*dirs.entry(cwd.clone()).or_default() += size;
} }
}
}
let mut dirs_recursive: HashMap<&Path, usize> = HashMap::new(); let size: usize = size.parse().unwrap();
for (dir, size) in &dirs { for dir in cwd.parents() {
for parent in std::iter::successors(Some(&**dir), |dir| dir.parent()) { *dirs.entry(dir.to_path_buf()).or_default() += size;
*dirs_recursive.entry(parent).or_default() += size; }
} }
} }
println!( println!(
"{}", "{}",
dirs_recursive dirs.values().filter(|&&s| s <= 100_000).sum::<usize>()
.values()
.filter(|&&s| s <= 100_000)
.sum::<usize>()
); );
const TOTAL_SPACE: usize = 70_000_000; println!("{}", find_dir_to_delete(&dirs));
const REQUIRED_SPACE: usize = 30_000_000;
let unused = TOTAL_SPACE - dirs_recursive[&*PathBuf::from("/")];
let to_free = REQUIRED_SPACE - unused;
let mut sizes: Vec<_> = dirs_recursive.values().copied().collect();
sizes.sort_unstable();
let size = match sizes.binary_search(&to_free) {
Ok(i) => sizes[i],
Err(larger) => sizes[larger],
};
println!("{}", size);
} }