Day 07

src/day07/mod.rs

@@ -1,18 +1,68 @@
 use crate::read;
 use itertools::Itertools;
-use tuple_map::*;
+use indextree::Arena;
+
+#[derive(Debug)]
+struct Directory {
+    pub size: usize,
+    pub name: String
+}
 
 pub fn run() {
-    let input = read("04");
-    let lines = input.lines();
-    let lines = input.split("\n\n");
+    let arena = &mut Arena::new();
+    let mut current_directory = arena.new_node(Directory {
+        size: 0,
+        name: "/".into(),
+    });
+    let root = current_directory;
+
+    for line in read("07").lines().skip(1) {
+        if line.starts_with("$ cd") {
+            current_directory = match line.split_once("cd ").unwrap().1 {
+                dirname if ".." == dirname => current_directory.ancestors(arena).nth(1).unwrap(),
+                dirname => current_directory
+                    .children(arena)
+                    .find(|c|arena.get(*c).unwrap().get().name == dirname)
+                    .unwrap_or_else(||{
+                        let nc = arena.new_node(Directory {
+                            size: 0,
+                            name: dirname.into(),
+                        });
+                        current_directory.append(nc, arena);
+                        nc
+                    })
+            };
+        } else if line.chars().next().unwrap().is_numeric() {
+            let filesize: usize = line.split_once(" ").unwrap().0.parse().unwrap();
+            arena.get_mut(current_directory).unwrap().get_mut().size += filesize;
+        }
+    }
+    let total = root.descendants(arena).map(|desc|{
+        desc
+            .descendants(arena)
+            .map(|d|arena.get(d).unwrap().get().size)
+            .sum::<usize>()
+    }).collect::<Vec<_>>();
+
     #[cfg(feature = "part1")]
     {
-        println!("Day 7, Part 01: {}", "TODO");
+        println!("Day 7, Part 01: {}", total.clone().iter()
+            .filter(|s| *s <= &100000)
+            .sum::<usize>());
     }
 
     #[cfg(feature = "part2")]
     {
-        println!("Day 7, Part 02: {}", "TODO");
+        let total_used = root.descendants(arena)
+            .map(|d|arena.get(d).unwrap().get().size)
+            .sum::<usize>();
+        let free_needed = total_used - 40000000;
+
+        println!("Day 7, Part 02: {}", total.iter()
+            .filter(|s|*s >= &free_needed)
+            .sorted()
+            .next()
+            .unwrap());
     }
 }
+