day 7

src/bin/day07_1.rs

@@ -0,0 +1,8 @@
+use std::fs;
+
+use aoc2022::day07::process_part_1;
+
+fn main() {
+    let file = fs::read_to_string("./inputs/day7.txt").unwrap();
+    println!("{}", process_part_1(&file));
+}

src/bin/day07_2.rs

@@ -0,0 +1,8 @@
+use std::fs;
+
+use aoc2022::day07::process_part_2;
+
+fn main() {
+    let file = fs::read_to_string("./inputs/day7.txt").unwrap();
+    println!("{}", process_part_2(&file));
+}

src/day06.rs

@@ -1,4 +1,4 @@
-use itertools::Itertools;
+use std::collections::BTreeSet;
 
 pub fn process_part_1(input: &str) -> usize {
     find_unique_window_start(input, 4)
@@ -14,7 +14,7 @@ pub fn find_unique_window_start(input: &str, window_size: usize) -> usize {
             .chars()
             .collect::<Vec<_>>()
             .windows(window_size)
-            .take_while(|x| x.iter().unique().count() != x.len())
+            .take_while(|x| x.iter().collect::<BTreeSet<_>>().len() != x.len())
             .count()
 }
 

src/day07.rs

@@ -0,0 +1,158 @@
+use std::collections::BTreeMap;
+
+use nom::branch::alt;
+use nom::bytes::complete::{tag, take_till1};
+use nom::character::complete::{newline, space1};
+use nom::character::{complete, is_newline};
+use nom::multi::separated_list1;
+use nom::IResult;
+
+pub fn process_part_1(input: &str) -> u32 {
+    let (_, commands) = parse_commands(input).unwrap();
+    let directories = build_directory_tree_from_commands(commands);
+
+    directories.values().filter(|size| **size <= 100_000).sum()
+}
+
+pub fn process_part_2(input: &str) -> u32 {
+    let (_, commands) = parse_commands(input).unwrap();
+    let directories = build_directory_tree_from_commands(commands);
+
+    let total_space = 70_000_000;
+    let required_space = 30_000_000;
+    let current_space = total_space - *directories.get("").unwrap();
+    let wanted_space = required_space - current_space;
+
+    directories
+        .values()
+        .filter(|size| **size >= wanted_space)
+        .map(|size| *size)
+        .min()
+        .unwrap_or(0)
+}
+
+fn build_directory_tree_from_commands(commands: Vec<Command>) -> BTreeMap<String, u32> {
+    let mut cwd: Vec<&str> = vec![];
+    let mut directories: BTreeMap<String, u32> = BTreeMap::new();
+    for command in commands {
+        match command {
+            Command::Cd("/") => {
+                cwd = vec![];
+            }
+            Command::Cd("..") => {
+                cwd.pop();
+            }
+            Command::Cd(name) => {
+                cwd.push(name);
+            }
+            Command::Ls(files) => {
+                for file in files {
+                    match file {
+                        DirEntry::File { name: _name, size } => {
+                            for i in 0..=cwd.len() {
+                                directories
+                                    .entry(cwd[..i].join("/"))
+                                    .and_modify(|f| *f += size)
+                                    .or_insert(size);
+                            }
+                        }
+                        _ => {}
+                    }
+                }
+            }
+        }
+    }
+    directories
+}
+
+#[derive(Debug)]
+enum Command<'a> {
+    Cd(&'a str),
+    Ls(Vec<DirEntry<'a>>),
+}
+
+#[derive(Debug)]
+enum DirEntry<'a> {
+    Dir(&'a str),
+    File { name: &'a str, size: u32 },
+}
+
+fn parse_commands(input: &str) -> IResult<&str, Vec<Command>> {
+    separated_list1(newline, parse_command)(input)
+}
+
+fn parse_command(input: &str) -> IResult<&str, Command> {
+    let (input, _) = tag("$ ")(input)?;
+    alt((parse_cd, parse_ls))(input)
+}
+
+fn parse_cd(input: &str) -> IResult<&str, Command> {
+    let (input, _) = tag("cd")(input)?;
+    let (input, _) = space1(input)?;
+    let (input, arg) = parse_file_name(input)?;
+    Ok((input, Command::Cd(arg)))
+}
+
+fn parse_ls(input: &str) -> IResult<&str, Command> {
+    let (input, _) = tag("ls")(input)?;
+    let (input, _) = newline(input)?;
+    let (input, entries) =
+        separated_list1(tag("\n"), alt((parse_dir_entry_dir, parse_dir_entry_file)))(input)?;
+    Ok((input, Command::Ls(entries)))
+}
+
+fn parse_dir_entry_dir(input: &str) -> IResult<&str, DirEntry> {
+    let (input, _) = tag("dir ")(input)?;
+    let (input, name) = parse_file_name(input)?;
+    Ok((input, DirEntry::Dir(name)))
+}
+
+fn parse_dir_entry_file(input: &str) -> IResult<&str, DirEntry> {
+    let (input, size) = complete::u32(input)?;
+    let (input, _) = tag(" ")(input)?;
+    let (input, name) = parse_file_name(input)?;
+    Ok((input, DirEntry::File { name, size }))
+}
+
+fn parse_file_name(input: &str) -> IResult<&str, &str> {
+    take_till1(|c| is_newline(c as u8))(input)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const INPUT: &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";
+
+    #[test]
+    fn day1() {
+        assert_eq!(process_part_1(INPUT), 95437);
+    }
+
+    #[test]
+    fn day2() {
+        assert_eq!(process_part_2(INPUT), 24933642);
+    }
+}

src/lib.rs

@@ -7,3 +7,4 @@ pub mod day03;
 pub mod day04;
 pub mod day05;
 pub mod day06;
+pub mod day07;