Add 2022/07/01

2022/src/bin/day07.rs

@@ -0,0 +1,135 @@
+#![feature(test)]
+extern crate test;
+use std::ops::{Index, IndexMut};
+
+use aoc2022::{boilerplate, common::*};
+
+const DAY: usize = 7;
+
+enum Node<'a> {
+    File(&'a str, usize),
+    Dir(&'a str, Vec<Box<Node<'a>>>),
+}
+
+impl<'a> IndexMut<&str> for Node<'a> {
+    fn index_mut(&mut self, index: &str) -> &mut Node<'a> {
+        match self {
+            Self::Dir(_, contents) => {
+                contents.iter_mut().find(|d| matches!(***d, Self::Dir ( name,_) if name == index)).expect("File not found")
+            }
+            Self::File(name, _) => panic!("Can’t index into a file ({name})"),
+        }
+    }
+}
+
+impl<'a> Index<&str> for Node<'a> {
+    type Output = Self;
+
+    fn index(&self, index: &str) -> &Self::Output {
+        match self {
+            Self::Dir(_, contents) => {
+                contents.iter().find(|&d| matches!(**d, Self::Dir ( name,_) if name == index)).expect("File not found")
+            }
+            Self::File(name, _) => panic!("Can’t index into a file ({name})"),
+        }
+    }
+}
+
+fn parse_input(raw: &str) -> Node<'_> {
+    let mut pwd = Vec::<&str>::new();
+    let mut fs = Node::Dir("/", Vec::new());
+    for cmd in raw.trim_start_matches("$ cd /\n$ ").split("$ ") {
+        // println!("Now at: {cmd}");
+        let mut lines = cmd.lines();
+        match lines.next().and_then(|s| s.split_once(' ')) {
+            Some(("cd", "..")) => {
+                pwd.pop();
+            }
+            Some(("cd", dir)) => pwd.push(dir),
+            // ls
+            _ => {
+                let mut cd = &mut fs;
+                for p in pwd.iter() {
+                    cd = &mut cd[p];
+                }
+                match cd {
+                    Node::Dir(_, contents) => {
+                        for line in lines {
+                            match line.split_once(' ') {
+                                Some(("dir", d)) => contents.push(Box::new(Node::Dir(d, Vec::new()))),
+                                Some((size, name)) => contents.push(Box::new(Node::File(name, size.parse().unwrap()))),
+                                _ => unreachable!("Invalid directory contents: {line}"),
+                            }
+                        }
+                    }
+                    Node::File(_, _) => unreachable!("Can’t `ls` file contents"),
+                }
+            }
+        };
+    }
+    fs
+}
+
+fn part1(parsed: &Node<'_>) -> usize {
+    let mut n = 0;
+    node_size(parsed, &mut n);
+    n
+}
+
+fn node_size(node: &Node<'_>, n: &mut usize) -> usize {
+    match node {
+        Node::File(_, s) => *s,
+        Node::Dir(_, c) => {
+            let dir_size = c.iter().map(|d| node_size(d, n)).sum();
+            if dir_size <= 100_000 {
+                *n += dir_size;
+            }
+            dir_size
+        }
+    }
+}
+
+fn part2(parsed: &Node<'_>) -> usize {
+    unimplemented!()
+}
+
+boilerplate! {
+    TEST_INPUT == "$ 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",
+    tests: {
+        part1: { TEST_INPUT => 95437 },
+        part2: { TEST_INPUT => 24933642 },
+    },
+    bench1 == 1667443,
+    bench2 == 0,
+    bench_parse: node_name => "/",
+}
+
+#[cfg(test)]
+fn node_name<'a>(n: &Node<'a>) -> &'a str {
+    match n {
+        Node::Dir(name, _) => name,
+        Node::File(name, _) => name,
+    }
+}