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finish day7

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This commit is contained in:
Joseph Montanaro 2022-12-08 10:14:48 -08:00
parent 393db1d3bf
commit 6abb28f96f
1 changed files with 85 additions and 37 deletions
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122
2022/src/day7.rs
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@ -24,10 +24,10 @@ enum Node {
lazy_static! { lazy_static! {
static ref CMD_CD: Regex = Regex::new(r"^\$ cd (\w+)$").unwrap(); static ref CMD_CD: Regex = Regex::new(r"^\$ cd (\S+)$").unwrap();
static ref CMD_LS: Regex = Regex::new(r"^\$ ls$").unwrap(); static ref CMD_LS: Regex = Regex::new(r"^\$ ls$").unwrap();
static ref DIR_LISTING: Regex = Regex::new(r"^dir (\w+)$").unwrap(); static ref DIR_LISTING: Regex = Regex::new(r"^dir (\S+)$").unwrap();
static ref FILE_LISTING: Regex = Regex::new(r"^(\d+) (\w+)$").unwrap(); static ref FILE_LISTING: Regex = Regex::new(r"^(\d+) (\S+)$").unwrap();
} }
@ -58,8 +58,13 @@ fn build_map(data: &str) -> Result<HashMap<usize, NodeListing>, String> {
'lines: for line in data.trim().lines() { 'lines: for line in data.trim().lines() {
if CMD_LS.is_match(line) {continue;} if CMD_LS.is_match(line) {continue;}
if let Some(m) = CMD_CD.find_iter(line).next() { if let Some(c) = CMD_CD.captures(line) {
let name = m.as_str(); let name = c.get(1).unwrap().as_str();
if name == "/" {
stack.truncate(1);
continue;
}
if name == ".." { if name == ".." {
stack.pop(); stack.pop();
continue; continue;
@ -69,13 +74,13 @@ fn build_map(data: &str) -> Result<HashMap<usize, NodeListing>, String> {
NodeListing::Branch(dir) => dir, NodeListing::Branch(dir) => dir,
_ => unreachable!(), _ => unreachable!(),
}; };
for id in current_dir.children { for id in &current_dir.children {
let child_name = match map.get(&id).unwrap() { let child_name = match map.get(&id).unwrap() {
NodeListing::Branch(dir) => dir.name, NodeListing::Branch(dir) => &dir.name,
NodeListing::Leaf(file) => file.name, NodeListing::Leaf(file) => &file.name,
}; };
if child_name == name { if child_name == name {
stack.push(id); stack.push(*id);
continue 'lines; continue 'lines;
} }
} }
@ -83,28 +88,27 @@ fn build_map(data: &str) -> Result<HashMap<usize, NodeListing>, String> {
return Err(format!("Attempted to cd into directory before ls-ing it: {}", line.to_string())); return Err(format!("Attempted to cd into directory before ls-ing it: {}", line.to_string()));
} }
if let Some(m) = DIR_LISTING.find_iter(line).next() { if let Some(c) = DIR_LISTING.captures(line) {
let parent_id = stack.last().unwrap(); let parent_id = stack.last().unwrap();
let child_id = map.len();
let parent = match map.get_mut(parent_id).unwrap() { let parent = match map.get_mut(parent_id).unwrap() {
NodeListing::Branch(dir) => dir, NodeListing::Branch(dir) => dir,
_ => unreachable!(), _ => unreachable!(),
}; };
parent.children.push(child_id);
let dir = DirListing { let dir = DirListing {
name: m.as_str().to_string(), name: c.get(1).unwrap().as_str().to_string(),
children: vec![], children: vec![],
parent: Some(*parent_id), parent: Some(*parent_id),
}; };
// this is safe as long as we never remove anything from the map while we're building it map.insert(child_id, NodeListing::Branch(dir));
let dir_id = map.len();
map.insert(dir_id, NodeListing::Branch(dir));
parent.children.push(dir_id);
continue; continue;
} }
let matches = FILE_LISTING.find_iter(line); if let Some(c) = FILE_LISTING.captures(line) {
if let (Some(s), Some(n)) = (matches.next(), matches.next()) { let name = c.get(2).unwrap().as_str().to_string();
let name = n.as_str().to_string(); let size = c.get(1).unwrap().as_str().parse::<usize>()
let size = s.as_str().parse::<usize>()
.map_err(|_e| format!("Invalid file size: {}", line.to_string()))?; .map_err(|_e| format!("Invalid file size: {}", line.to_string()))?;
let file_id = map.len(); let file_id = map.len();
@ -126,16 +130,15 @@ fn build_map(data: &str) -> Result<HashMap<usize, NodeListing>, String> {
} }
fn build_tree(map: &HashMap<usize, NodeListing>, root:&DirListing) -> Directory { fn build_tree(map: &mut HashMap<usize, NodeListing>, root_listing: &DirListing) -> Directory {
let root_listing = map.get(&root_id).unwrap(); let mut root_children = Vec::new();
let root_children = Vec::new(); for child_id in &root_listing.children {
for child_id in root_listing.children { match map.remove(&child_id).unwrap() {
match map.get(&child_id).unwrap() {
NodeListing::Leaf(file) => { NodeListing::Leaf(file) => {
root_children.push(Node::Leaf(file)); root_children.push(Node::Leaf(file));
}, },
NodeListing::Branch(dir_listing) => { NodeListing::Branch(dir_listing) => {
let dir = build_tree(map, child_id); let dir = build_tree(map, &dir_listing);
root_children.push(Node::Branch(dir)) root_children.push(Node::Branch(dir))
}, },
} }
@ -149,33 +152,78 @@ fn build_tree(map: &HashMap<usize, NodeListing>, root:&DirListing) -> Directory
fn get_sizes(root: &Directory, mut sizes: Vec<usize>) -> (usize, Vec<usize>) { fn get_sizes(root: &Directory, mut sizes: Vec<usize>) -> (usize, Vec<usize>) {
let dir_size = 0; let mut dir_size = 0;
let mut returned_sizes; for child in &root.children {
for child in root.children {
match child { match child {
Node::Leaf(file) => dir_size += file.size, Node::Leaf(file) => dir_size += file.size,
Node::Branch(dir) => { Node::Branch(dir) => {
let (child_size, rs) = get_sizes(dir, sizes); let (child_size, rs) = get_sizes(dir, sizes);
returned_sizes = rs; sizes = rs;
dir_size += child_size; dir_size += child_size;
}, },
} }
} }
returned_sizes.push(dir_size); sizes.push(dir_size);
returned_sizes (dir_size, sizes)
} }
fn main() -> Result<(), String> { fn main() -> Result<(), String> {
let map = build_map(data); let mut map = build_map(DATA)?;
let tree = build_tree(map, 0); let root = match map.remove(&0).unwrap() {
let (_total_size, dir_sizes) = get_sizes(&tree, vec![]); NodeListing::Branch(dir) => dir,
_ => unreachable!(),
};
let part1_sizes = dir_sizes.iter() let tree = build_tree(&mut map, &root);
.filter(|s| s <= 100000) let (total_size, dir_sizes) = get_sizes(&tree, vec![]);
let part1_sizes: usize = dir_sizes.iter()
.filter(|&&s| s <= 100000)
.sum(); .sum();
println!("Part 1: {part1_sizes}"); println!("Part 1: {part1_sizes}");
let available = 70_000_000 - total_size;
if available >= 30_000_000 {
return Err("Weird, there's already enough space available".to_string());
}
let target_size = 30_000_000 - available;
let delete_size = dir_sizes.iter()
.filter(|&&s| s >= target_size)
.min()
.unwrap();
println!("Part 2: {delete_size}");
Ok(())
} }
const DATA: &'static str = include_str!("../data/day7.txt");
// const DATA: &'static str = "
// $ cd /
// $ ls
// dir a
// 14848514 b.txt
// 8504156 c.dat
// dir d
// $ cd a
// $ ls
// dir e
// 29116 f
// 2557 g
// 62596 h.lst
// $ cd e
// $ ls
// 584 i
// $ cd ..
// $ cd ..
// $ cd d
// $ ls
// 4060174 j
// 8033020 d.log
// 5626152 d.ext
// 7214296 k
// ";