some formatting and some optimizations

day1/src/main.rs

@@ -1,25 +1,22 @@
 use std::fs::File;
 use std::io::{prelude::*, BufReader};
 
-fn main() -> std::io::Result<()>{
+fn main() -> std::io::Result<()> {
     let file = File::open("input")?;
     let reader = BufReader::new(file);
 
-    let mut elves = reader.lines()
-        .fold(Vec::new(), |mut acc, line| {
-            let line = line.unwrap();
-            //empty lines mean new elf
-            if line.is_empty() || acc.is_empty() {
-                acc.push(0_u64);
-            }
-
+    let mut elves = reader.lines().fold(vec![0_u64], |mut acc, line| {
+        let line = line.unwrap();
+        //empty lines mean new elf
+        if line.is_empty() {
+            acc.push(0_u64);
+        } else {
             // the first time through is an edge case preventing an else here
-            if ! line.is_empty() {
-                let last = acc.last_mut().unwrap();
-                *last += line.parse::<u64>().unwrap();
-            }
-            acc
-        });
+            let last = acc.last_mut().unwrap();
+            *last += line.parse::<u64>().unwrap();
+        }
+        acc
+    });
 
     //order the elves since we don't care about position anymore
     elves.sort();
@@ -29,7 +26,7 @@ fn main() -> std::io::Result<()>{
     println!("Part 1: {}", elves[max]);
 
     //Part 2 is get the sum of the largest 3
-    let counts: u64 = elves[(max-2)..].iter().sum();
+    let counts: u64 = elves[(max - 2)..].iter().sum();
     println!("Part 2: {counts}");
 
     Ok(())