2022 day1/rust: avoid unnecessary allocations

2022/day1/rust/src/main.rs

@@ -1,7 +1,13 @@
-use std::{cmp::Reverse, io::stdin};
+use std::{
+    cmp::Reverse,
+    io::{stdin, Read},
+};
 
 fn main() {
-    let lines: Vec<_> = stdin().lines().map(Result::unwrap).collect();
+    let mut data = String::new();
+    stdin().read_to_string(&mut data).unwrap();
+
+    let lines: Vec<_> = data.lines().collect();
     let mut elves: Vec<_> = lines
         .split(|s| s.is_empty())
         .map(|entries| {