Adding beginning of problem 8

id_tree is used for arbitrary trees of any number of child per node.
color_eyre is for better error output handling

Cargo.toml

@@ -12,4 +12,7 @@ rpath = true
 
 [dependencies]
 nom = "7.1.1"
-itertools = "0.10.5"
+itertools = "0.11.0"
+camino = "1.1.6"
+id_tree = "1.8.0"
+color-eyre = "0.6.2"

prob8_part1.txt

@@ -0,0 +1,99 @@
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src/lib.rs

@@ -5,3 +5,5 @@ pub mod prob4;
 pub mod prob5;
 pub mod prob6;
 pub mod prob7;
+
+pub mod prob8;

src/main.rs

@@ -1,6 +1,8 @@
-use advent_of_code::{prob1, prob2, prob3, prob4, prob5, prob6};
+use advent_of_code::{prob1, prob2, prob3, prob4, prob5, prob6, prob7};
+use color_eyre::eyre::Result;
 
-fn main() {
+fn main() -> Result<()> {
+    color_eyre::install()?;
     {
         let file_path = "prob1.txt";
         let max_part1 = prob1::solve_part1(file_path);
@@ -53,4 +55,14 @@ fn main() {
         let solution = prob6::solve_part2(include_str!("../prob6_part1.txt"));
         println!("Solution for problem 6 part 2: {solution}");
     }
+    {
+        let _file_path = "prob7_part1.txt";
+        let solution = prob7::solve_part1(include_str!("../prob7_part1.txt"))?;
+        println!("Solution for problem 7 part 1: {solution}");
+    }
+    {
+        let solution = prob7::solve_part2(include_str!("../prob7_part2.txt"))?;
+        println!("Solution for problem 7 part 2: {solution}");
+    }
+    Ok(())
 }

src/prob7.rs

@@ -1,17 +1,175 @@
-use nom::{branch::alt, bytes::complete::tag, combinator::map, IResult};
+use camino::Utf8PathBuf;
+use id_tree::{InsertBehavior, Node, Tree};
+use nom::{
+    branch::alt,
+    bytes::complete::{tag, take_while1},
+    combinator::{all_consuming, map},
+    sequence::{preceded, separated_pair},
+    Finish, IResult,
+};
 
-use crate::prob7::Instructions::{Cd, Dir, Ls};
+#[derive(Debug)]
+struct Ls;
 
-enum Instructions {
+#[derive(Debug)]
+struct Cd(Utf8PathBuf);
+
+#[derive(Debug)]
+enum Entry {
+    Dir(Utf8PathBuf),
+    File(u64, Utf8PathBuf),
+}
+
+#[derive(Debug)]
+enum Command {
     Ls,
-    Cd,
-    Dir,
+    Cd(Utf8PathBuf),
 }
 
-fn parse_instruction(i: &str) -> IResult<&str, Instructions> {
-    alt((
-        map(tag("ls"), |_| Ls),
-        map(tag("cd"), |_| Cd),
-        map(tag("dir"), |_| Dir),
-    ))(i)
+#[derive(Debug)]
+enum Line {
+    Command(Command),
+    Entry(Entry),
+}
+
+impl From<Ls> for Command {
+    fn from(_ls: Ls) -> Self {
+        Command::Ls
+    }
+}
+
+impl From<Cd> for Command {
+    fn from(cd: Cd) -> Self {
+        Command::Cd(cd.0)
+    }
+}
+
+#[derive(Debug, Default)]
+struct FsEntry {
+    path: Utf8PathBuf,
+    size: u64,
+}
+
+fn parse_entry(input: &str) -> IResult<&str, Entry> {
+    let parse_file = map(
+        separated_pair(nom::character::complete::u64, tag(" "), parse_path),
+        |(size, path)| Entry::File(size, path),
+    );
+    let parse_dir = map(preceded(tag("dir "), parse_path), Entry::Dir);
+
+    alt((parse_file, parse_dir))(input)
+}
+
+fn parse_path(input: &str) -> IResult<&str, Utf8PathBuf> {
+    map(
+        take_while1(|c: char| "abcdefghijklmnopqrstuvwxyz./".contains(c)),
+        Into::into,
+    )(input)
+}
+
+fn parse_ls(input: &str) -> IResult<&str, Ls> {
+    map(tag("ls"), |_| Ls)(input)
+}
+fn parse_cd(input: &str) -> IResult<&str, Cd> {
+    map(preceded(tag("cd "), parse_path), Cd)(input)
+}
+
+fn parse_command(line: &str) -> IResult<&str, Command> {
+    let (input, _) = tag("$ ")(line)?;
+    alt((map(parse_ls, Into::into), map(parse_cd, Into::into)))(input)
+}
+
+fn parse_line(input: &str) -> IResult<&str, Line> {
+    alt((
+        map(parse_command, Line::Command),
+        map(parse_entry, Line::Entry),
+    ))(input)
+}
+
+fn total_size(tree: &Tree<FsEntry>, node: &Node<FsEntry>) -> color_eyre::Result<u64> {
+    let mut total = node.data().size;
+    for child in node.children() {
+        total += total_size(tree, tree.get(child)?)?;
+    }
+    Ok(total)
+}
+
+fn generate_tree(content: &str) -> color_eyre::Result<Tree<FsEntry>> {
+    let lines = content.lines().map(|line| {
+        all_consuming(parse_line)(line)
+            .finish()
+            .unwrap_or_else(|err| panic!("{err}"))
+            .1
+    });
+
+    let mut tree = Tree::<FsEntry>::new();
+    let root = tree.insert(
+        Node::new(FsEntry {
+            path: "/".into(),
+            size: 0,
+        }),
+        InsertBehavior::AsRoot,
+    )?;
+    let mut curr = root;
+
+    for line in lines {
+        match line {
+            Line::Command(cmd) => match cmd {
+                Command::Ls => {}
+                Command::Cd(path) => match path.as_str() {
+                    "/" => {}
+                    ".." => {
+                        curr = tree.get(&curr)?.parent().unwrap().clone();
+                    }
+                    _ => {
+                        curr = tree.insert(
+                            Node::new(FsEntry {
+                                path: path.clone(),
+                                size: 0,
+                            }),
+                            InsertBehavior::UnderNode(&curr),
+                        )?;
+                    }
+                },
+            },
+            Line::Entry(entry) => match entry {
+                Entry::Dir(_) => {}
+                Entry::File(size, name) => {
+                    tree.insert(
+                        Node::new(FsEntry { path: name, size }),
+                        InsertBehavior::UnderNode(&curr),
+                    )?;
+                }
+            },
+        }
+    }
+    Ok(tree)
+}
+
+pub fn solve_part1(content: &str) -> color_eyre::Result<u64> {
+    let tree = generate_tree(content)?;
+    let sum = tree
+        .traverse_pre_order(tree.root_node_id().unwrap())?
+        .filter(|n| !n.children().is_empty())
+        .map(|n| total_size(&tree, n).unwrap())
+        .filter(|&s| s <= 100_000)
+        .sum::<u64>();
+    Ok(sum)
+}
+
+pub fn solve_part2(content: &str) -> color_eyre::Result<u64> {
+    let total_space = 70000000_u64;
+    let tree = generate_tree(content)?;
+    let used_space = total_size(&tree, tree.get(tree.root_node_id().unwrap())?)?;
+    let free_space = total_space.checked_sub(used_space).unwrap();
+    let needed_free_space = 30000000_u64;
+    let minimum_space_to_free = needed_free_space.checked_sub(free_space).unwrap();
+
+    let size_to_remove = tree
+        .traverse_pre_order(tree.root_node_id().unwrap())?
+        .filter(|n| !n.children().is_empty())
+        .map(|n| total_size(&tree, n).unwrap())
+        .filter(|&s| s >= minimum_space_to_free)
+        .min().unwrap();
+    Ok(size_to_remove)
 }