169 lines
4.5 KiB
Rust
169 lines
4.5 KiB
Rust
use eyes::parse;
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use itertools::Itertools;
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use std::{cell::RefCell, collections::HashMap, iter, rc::Rc};
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fn main() {
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let input = aoc::input!();
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println!("part 1: {}", part1(&input));
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println!("part 1: {}", part2(&input));
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}
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type RefNode = Rc<RefCell<Node>>;
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#[derive(Default)]
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struct Node {
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size: u64,
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children: HashMap<String, RefNode>,
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parent: Option<RefNode>,
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}
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impl Node {
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fn total_size(&self) -> u64 {
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self.children
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.values()
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.map(|child| child.borrow().total_size())
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.sum::<u64>()
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+ self.size
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}
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}
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fn all_dirs(n: RefNode) -> Box<dyn Iterator<Item = RefNode>> {
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let children = n.borrow().children.values().cloned().collect::<Vec<_>>();
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Box::new(
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iter::once(n).chain(
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children
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.into_iter()
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.filter_map(|c| {
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if c.borrow().size == 0 {
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Some(all_dirs(c))
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} else {
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None
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}
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})
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.flatten(),
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),
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)
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}
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fn part1(input: &str) -> u64 {
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let root = RefNode::default();
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let mut node = root.clone();
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for line in input.lines() {
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match line {
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l if l.starts_with("$ cd") => {
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let dir = parse!(l, "$ cd {}", String);
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match dir.as_str() {
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"/" => continue,
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".." => {
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let parent = node.borrow().parent.clone().unwrap();
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node = parent;
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}
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_ => {
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let child = node.borrow_mut().children.entry(dir).or_default().clone();
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node = child;
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}
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}
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} // cd
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l if l.starts_with("$ ls") => continue, // ls
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l if l.starts_with("dir ") => {
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// dir entry
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let dir = parse!(l, "dir {}", String);
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let entry = node.borrow_mut().children.entry(dir).or_default().clone();
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entry.borrow_mut().parent = Some(node.clone());
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}
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l => {
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// file entry
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let (size, file) = parse!(l, "{} {}", u64, String);
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let entry = node.borrow_mut().children.entry(file).or_default().clone();
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entry.borrow_mut().size = size;
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entry.borrow_mut().parent = Some(node.clone());
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}
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}
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}
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all_dirs(root)
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.map(|d| d.borrow().total_size())
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.filter(|&s| s <= 100_000)
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.sum::<u64>()
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}
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fn part2(input: &str) -> u64 {
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let root = RefNode::default();
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let mut node = root.clone();
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for line in input.lines() {
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match line {
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l if l.starts_with("$ cd") => {
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let dir = parse!(l, "$ cd {}", String);
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match dir.as_str() {
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"/" => continue,
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".." => {
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let parent = node.borrow().parent.clone().unwrap();
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node = parent;
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}
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_ => {
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let child = node.borrow_mut().children.entry(dir).or_default().clone();
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node = child;
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}
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}
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} // cd
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l if l.starts_with("$ ls") => continue, // ls
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l if l.starts_with("dir ") => {
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// dir entry
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let dir = parse!(l, "dir {}", String);
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let entry = node.borrow_mut().children.entry(dir).or_default().clone();
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entry.borrow_mut().parent = Some(node.clone());
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}
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l => {
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// file entry
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let (size, file) = parse!(l, "{} {}", u64, String);
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let entry = node.borrow_mut().children.entry(file).or_default().clone();
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entry.borrow_mut().size = size;
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entry.borrow_mut().parent = Some(node.clone());
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}
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}
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}
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let free_space = 70000000 - root.borrow().total_size();
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all_dirs(root)
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.map(|d| d.borrow().total_size())
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.filter(|&s| s >= 30000000 - free_space)
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.min()
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.unwrap()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn examples() {
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let example = r#"$ cd /
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$ ls
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dir a
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14848514 b.txt
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8504156 c.dat
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dir d
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$ cd a
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$ ls
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dir e
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29116 f
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2557 g
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62596 h.lst
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$ cd e
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$ ls
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584 i
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$ cd ..
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$ cd ..
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$ cd d
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$ ls
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4060174 j
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8033020 d.log
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5626152 d.ext
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7214296 k"#;
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assert_eq!(part1(example), 95437);
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assert_eq!(part2(example), 24933642);
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}
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}
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