2022 day7/rust: cleanup

This commit is contained in:
Xiretza 2022-12-07 19:16:30 +01:00
parent 5d846eb88c
commit a74b1f4bc6
1 changed files with 37 additions and 51 deletions

View File

@ -1,76 +1,62 @@
#![warn(clippy::pedantic)]
use std::{
collections::HashMap,
hash::Hash,
io::{stdin, Read},
path::{Path, PathBuf},
};
use std::{collections::HashMap, io::stdin, 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() {
let mut data = String::new();
stdin().read_to_string(&mut data).unwrap();
let mut cwd = PathBuf::new();
cwd.push("/");
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("$ ") {
let mut args = command.split_whitespace();
let command = args.next().unwrap();
match command {
"ls" => {
dirs.remove(&cwd);
if args.next().unwrap() != "cd" {
continue;
}
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 {
let (size, _name) = line.split_once(' ').unwrap();
let size = line.split_whitespace().next().unwrap();
if size == "dir" {
// skip
} else {
let size: usize = size.parse().unwrap();
*dirs.entry(cwd.clone()).or_default() += size;
continue;
}
}
}
let mut dirs_recursive: HashMap<&Path, usize> = HashMap::new();
for (dir, size) in &dirs {
for parent in std::iter::successors(Some(&**dir), |dir| dir.parent()) {
*dirs_recursive.entry(parent).or_default() += size;
let size: usize = size.parse().unwrap();
for dir in cwd.parents() {
*dirs.entry(dir.to_path_buf()).or_default() += size;
}
}
}
println!(
"{}",
dirs_recursive
.values()
.filter(|&&s| s <= 100_000)
.sum::<usize>()
dirs.values().filter(|&&s| s <= 100_000).sum::<usize>()
);
const TOTAL_SPACE: usize = 70_000_000;
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);
println!("{}", find_dir_to_delete(&dirs));
}