day 2 solution, minor refactors.

src/day01/parse.rs

@@ -2,14 +2,13 @@
 pub struct Elf(pub Vec<usize>);
 
 pub fn parse(input: &str) -> Vec<Elf> {
-    input.trim()
+    input
+        .trim()
         .split("\n\n")
         .map(|group| {
             Elf(group
                 .split('\n')
-                .map(|line| {
-                    line.parse().unwrap()
-                })
+                .map(|line| line.parse().unwrap())
                 .collect())
         })
         .collect::<Vec<Elf>>()

src/day01/part2.rs

@@ -1,10 +1,12 @@
 use crate::parse;
 
 pub fn part2(input: &[parse::Elf]) -> usize {
-    input
+    let mut input = input
         .iter()
         .map(|elf| elf.0.iter().sum::<usize>())
-        // not sure what to do next here, how do I get the 3 max values from here?
+        .collect::<Vec<usize>>();
+    input.sort_unstable();
+    input[input.len() - 3..].iter().sum()
 }
 
 #[cfg(test)]

src/day01/solve.rs

@@ -1,6 +1,6 @@
+mod parse;
 mod part1;
 mod part2;
-mod parse;
 
 fn main() {
     let _input = include_str!("./input.txt");