Replace .split('\n') with .lines()`

src/bin/d1.rs

@@ -4,7 +4,7 @@ fn main() -> anyhow::Result<()> {
     let mut elves = INPUT
         .split("\n\n")
         .map(|elf| {
-            elf.split('\n')
+            elf.lines()
                 .map(|s| s.parse::<usize>().expect("Failed to parse input"))
                 .sum::<usize>()
         })

src/bin/d3.rs

@@ -4,7 +4,7 @@ const INPUT: &str = include_str!("../input/d3.txt");
 
 fn main() -> anyhow::Result<()> {
     let p1 = INPUT
-        .split('\n')
+        .lines()
         .map(|s| s.split_at(s.len() / 2))
         .map(|(l, r)| {
             l.chars().find(|ch| {
@@ -15,7 +15,7 @@ fn main() -> anyhow::Result<()> {
         .sum::<usize>();
     println!("{p1}");
     let p2 = INPUT
-        .split('\n')
+        .lines()
         .batching(|it| {
             it.next_tuple::<(&str,&str,&str)>()
         })

src/bin/d4.rs

@@ -2,13 +2,13 @@ const INPUT: &str = include_str!("../input/d4.txt");
 
 fn main() -> anyhow::Result<()> {
     let p1 = INPUT
-        .split('\n')
+        .lines()
         .map(Pair::from)
         .filter(ranges_contain_each_other)
         .count();
     println!("{p1}");
     let p2 = INPUT
-        .split('\n')
+        .lines()
         .map(Pair::from)
         .filter(ranges_overlap)
         .count();

src/bin/d5.rs

@@ -19,7 +19,7 @@ fn main() -> anyhow::Result<()> {
     ];
     let mut p1c = input.clone();
     let p1m = moves
-        .split('\n')
+        .lines()
         .map(Move::from);
     for mv in p1m {
         for _ in 0..mv.0 {
@@ -34,7 +34,7 @@ fn main() -> anyhow::Result<()> {
     println!("{p1}");
     let mut p2c = input;
     let p2m = moves
-        .split('\n')
+        .lines()
         .map(Move::from);
     for mv in p2m {
         let mut temp = vec![];