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#![allow(dead_code)]
#![allow(unused_variables)]
use advent_of_code::prelude::*;
pub enum Node {
Dir,
File(u64),
}
impl Node {
fn new_dir() -> Self {
Self::Dir
}
fn new_file(size: u64) -> Self {
Self::File(size)
}
fn size(&self) -> u64 {
match self {
Self::Dir => 0,
Self::File(size) => *size,
}
}
}
fn tree_size(tree: &Tree<String, Node>) -> u64 {
tree.bfs().map(|(_, tree)| tree.data().size()).sum()
}
pub fn parse(fh: File) -> Result<Tree<String, Node>> {
let mut lines = parse::raw_lines(fh).peekable();
let mut root = Tree::new(Node::Dir);
let mut path = vec![];
while let Some(cmdline) = lines.by_ref().next() {
let Some(captures) = ®ex_captures!(
r"^\$ (cd|ls)(?: (.*))?$",
&cmdline
)
else { bail!("didn't match cmdline: '{}'", cmdline) };
let Some(cmd) = captures.get(1)
else { bail!("no cmd found in cmdline: '{}'", cmdline) };
let pwd = root.at_mut(&path).unwrap();
match cmd.as_str() {
"cd" => {
let Some(arg) = captures.get(2)
else { bail!("no arg found for cd: '{}'", cmdline) };
match arg.as_str() {
".." => {
path.pop();
}
"/" => path = vec![],
dirname => {
if pwd.at(&[dirname.to_string()]).is_none() {
pwd.add_child(
dirname.to_string(),
Node::new_dir(),
);
}
path.push(dirname.to_string());
}
}
}
"ls" => loop {
let Some(lsline) = lines.peek()
else { break };
let Some(captures) = ®ex_captures!(
r"^(dir|[0-9]+) (.*)$",
lsline
)
else { break };
let Some(data) = captures.get(1)
else { break };
let Some(name) = captures.get(2)
else { break };
let node = match data.as_str() {
"dir" => Node::new_dir(),
size => Node::new_file(size.parse().unwrap()),
};
pwd.add_child(name.as_str().to_string(), node);
lines.next();
},
_ => unreachable!(),
}
}
Ok(root)
}
pub fn part1(tree: Tree<String, Node>) -> Result<u64> {
let mut total = 0;
for (_, tree) in tree.bfs() {
if matches!(tree.data(), Node::File(_)) {
continue;
}
let size = tree_size(tree);
if size <= 100_000 {
total += size;
}
}
Ok(total)
}
pub fn part2(tree: Tree<String, Node>) -> Result<u64> {
let total = tree_size(&tree);
let free = 70_000_000 - total;
let needed = 30_000_000 - free;
let mut possible = vec![];
for (_, tree) in tree.bfs() {
if matches!(tree.data(), Node::File(_)) {
continue;
}
let size = tree_size(tree);
if size > needed {
possible.push(size);
}
}
Ok(possible.iter().copied().min().unwrap())
}
#[test]
fn test() {
assert_eq!(
part1(parse(parse::data(2022, 7).unwrap()).unwrap()).unwrap(),
1297683
);
assert_eq!(
part2(parse(parse::data(2022, 7).unwrap()).unwrap()).unwrap(),
5756764
);
}
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