Improve day07

Cargo.lock

@@ -117,9 +117,6 @@ dependencies = [
 [[package]]
 name = "day07"
 version = "0.1.0"
-dependencies = [
- "ego-tree",
-]
 
 [[package]]
 name = "day08"
@@ -189,12 +186,6 @@ version = "0.1.0"
 name = "day24"
 version = "0.1.0"
 
-[[package]]
-name = "ego-tree"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3a68a4904193147e0a8dec3314640e6db742afd5f6e634f428a6af230d9b3591"
-
 [[package]]
 name = "errno"
 version = "0.2.8"

day07/Cargo.toml

@@ -8,4 +8,3 @@ build = true
 app = true
 
 [dependencies]
-ego-tree = "0.6.2"

day07/src/main.rs

@@ -1,13 +1,13 @@
-use ego_tree::NodeId;
+#![feature(binary_heap_into_iter_sorted)]
+
 use std::{
+    cmp::Reverse,
+    collections::BinaryHeap,
     fs::File,
     io::{BufRead, BufReader},
+    path::PathBuf,
 };
 
-type NodeMut<'t> = ego_tree::NodeMut<'t, Node>;
-type NodeRef<'t> = ego_tree::NodeRef<'t, Node>;
-type Tree = ego_tree::Tree<Node>;
-
 #[derive(Debug, Default, PartialEq, Eq)]
 enum SolvePuzzle {
     First,
@@ -16,147 +16,95 @@ enum SolvePuzzle {
 }
 
 #[derive(Debug)]
-struct Node {
-    label: String,
-    size: Option<usize>,
-    dir: bool,
+struct Collector<Ext: CollectorExt> {
+    pwd: PathBuf,
+    sums: Vec<usize>,
+    ext: Ext,
 }
 
-struct TreeParser {
-    tree: Tree,
-    curr_node: NodeId,
-    reading_dir_list: bool,
+trait CollectorExt: Default {
+    fn change_directory_up(&mut self, dir_size: usize);
 }
 
-impl TreeParser {
-    pub fn new() -> Self {
-        let tree = Tree::new(Node {
-            label: String::from("/"),
-            size: None,
-            dir: true,
-        });
-        Self {
-            curr_node: tree.root().id(),
-            tree,
-            reading_dir_list: false,
-        }
-    }
+#[derive(Debug, Default)]
+struct PartOne {
+    small_dirs_sum: usize,
+}
 
-    fn read(&mut self, line: &str) {
-        self.reading_dir_list &= !line.starts_with("$");
+#[derive(Debug, Default)]
+struct PartTwo {
+    smallest_relevant_dirs: BinaryHeap<Reverse<usize>>,
+}
+
+impl<Ext: CollectorExt> Collector<Ext> {
+    pub fn push_line<S: AsRef<str>>(&mut self, line: S) {
+        let line = line.as_ref();
         if line == "$ cd /" {
-            self.curr_node = self.tree.root().id();
+            self.change_director_root()
         } else if line == "$ cd .." {
-            let node = self.curr_node();
-            self.curr_node = node.parent().unwrap().id();
+            self.change_directory_up()
         } else if line.starts_with("$ cd ") {
-            let node = self.curr_node();
             let target = &line[5..];
-            let target = node
-                .children()
-                .find(|child| child.value().label == target)
-                .expect("Cd target exists");
-            self.curr_node = target.id();
+            self.change_directory_to(target)
         } else if line == "$ ls" {
-            self.reading_dir_list = true;
-        } else if self.reading_dir_list == true && line.starts_with("dir ") {
-            let label = &line[4..];
-            let mut node = self.curr_node_mut();
-            node.append(Node {
-                label: label.to_owned(),
-                size: None,
-                dir: true,
-            });
-        } else if self.reading_dir_list {
-            let (size, label) = line.split_once(' ').expect("A dir list entry");
-            let mut node = self.curr_node_mut();
-            node.append(Node {
-                label: label.to_owned(),
-                size: Some(size.parse().expect("Filesize is number")),
-                dir: false,
-            });
+            // Just ignore
+        } else if line.starts_with("dir ") {
+            // Nothing to do
         } else {
-            panic!("What? {:?}", line);
+            let (size, _label) = line.split_once(' ').expect("A dir list entry");
+            self.push_file(size.parse().expect("A number for dir size"))
         }
     }
 
-    fn curr_node(&self) -> NodeRef {
-        self.tree.get(self.curr_node).unwrap()
+    fn change_director_root(&mut self) {
+        while self.pwd.as_os_str() != "/" {
+            self.change_directory_up()
+        }
     }
 
-    fn curr_node_mut(&mut self) -> NodeMut {
-        self.tree.get_mut(self.curr_node).unwrap()
+    fn change_directory_up(&mut self) {
+        let this_dir_size = self.sums.pop().expect("At least two elements here");
+        *self.sums.last_mut().expect("At least one element here") += this_dir_size;
+        self.pwd.pop();
+        self.ext.change_directory_up(this_dir_size)
     }
 
-    fn finish(mut self) -> Tree {
-        let node_id = self.tree.root().id();
-        fill_size(&mut self.tree, node_id);
-        self.tree
+    fn change_directory_to(&mut self, target: &str) {
+        self.pwd.push(target);
+        self.sums.push(0);
     }
-}
 
-fn fill_size(tree: &mut Tree, node_id: NodeId) {
-    let node_ref = tree.get(node_id);
-    let missing: Vec<_> = {
-        node_ref
-            .unwrap()
-            .children()
-            .filter(|child| child.value().size.is_none())
-            .map(|child| child.id())
-            .collect()
-    };
-    for miss in missing {
-        fill_size(tree, miss);
+    fn push_file(&mut self, size: usize) {
+        *self.sums.last_mut().expect("At least one element here") += size;
     }
-    let node_ref = tree.get(node_id);
-    let size = node_ref
-        .unwrap()
-        .children()
-        .map(|child| child.value().size)
-        .map(Option::unwrap)
-        .sum();
-    tree.get_mut(node_id).unwrap().value().size = Some(size);
 }
 
 fn solve_first_puzzle<R: BufRead>(reader: R) -> usize {
-    let parser = reader
+    reader
         .lines()
         .map(Result::unwrap)
-        .fold(TreeParser::new(), |mut parser, line| {
-            parser.read(&line);
-            parser
-        });
-    let tree = parser.finish();
-    tree.nodes()
-        .map(|node_ref| node_ref.value())
-        .filter(|node| node.dir == true)
-        .map(|node| node.size.unwrap())
-        .filter(|&size| size <= 100000)
-        .sum()
+        .collect::<Collector<PartOne>>()
+        .ext
+        .small_dirs_sum
 }
 
 fn solve_second_puzzle<R: BufRead>(reader: R) -> usize {
     const REQUIRED_SIZE: usize = 30_000_000;
     const TOTAL: usize = 70_000_000;
-    let parser = reader
+    let col = reader
         .lines()
         .map(Result::unwrap)
-        .fold(TreeParser::new(), |mut parser, line| {
-            parser.read(&line);
-            parser
-        });
-    let tree = parser.finish();
-    let root_size = tree.root().value().size.unwrap();
+        .collect::<Collector<PartTwo>>();
+    let root_size = col.sums.first().unwrap();
     let free = TOTAL - root_size;
     let missing = REQUIRED_SIZE.saturating_sub(free);
-    tree.nodes()
-        .map(|node_ref| node_ref.value())
-        .filter(|node| node.dir == true)
-        .map(|node| node.size)
-        .map(Option::unwrap)
-        .filter(|&size| size >= missing)
-        .min()
-        .expect("At least one node")
+    col.ext
+        .smallest_relevant_dirs
+        .into_iter_sorted()
+        .find(|&Reverse(size)| size >= missing)
+        // There is at least the root dir
+        .unwrap()
+        .0
 }
 
 fn main() {
@@ -178,6 +126,47 @@ fn main() {
     println!("{}", solution);
 }
 
+impl<S, Ext> FromIterator<S> for Collector<Ext>
+where
+    S: AsRef<str>,
+    Ext: CollectorExt,
+{
+    fn from_iter<T: IntoIterator<Item = S>>(iter: T) -> Self {
+        let mut col = iter.into_iter().fold(Self::default(), |mut acc, line| {
+            let line = line.as_ref();
+            acc.push_line(line);
+            acc
+        });
+        col.change_director_root();
+        col
+    }
+}
+
+impl<Ext: CollectorExt> Default for Collector<Ext> {
+    fn default() -> Self {
+        Self {
+            ext: Ext::default(),
+            pwd: PathBuf::from("/"),
+            sums: vec![0],
+        }
+    }
+}
+
+impl CollectorExt for PartOne {
+    fn change_directory_up(&mut self, dir_size: usize) {
+        const SMALL_DIR_MAX_SIZE: usize = 100000;
+        if dir_size < SMALL_DIR_MAX_SIZE {
+            self.small_dirs_sum += dir_size;
+        }
+    }
+}
+
+impl CollectorExt for PartTwo {
+    fn change_directory_up(&mut self, dir_size: usize) {
+        self.smallest_relevant_dirs.push(Reverse(dir_size))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::io::Cursor;