diff --git a/src/2024/day1/rust/mod.rs b/src/2024/day1/rust/mod.rs
index 44dd4ec..0e991d1 100644
--- a/src/2024/day1/rust/mod.rs
+++ b/src/2024/day1/rust/mod.rs
@@ -1,43 +1,41 @@
 pub fn part_a(input: &str) -> i32 {
-    let mut left_list: Vec<i32> = Vec::new();
-    let mut right_list: Vec<i32> = Vec::new();
-    for line in input.lines() {
-        let parts: Vec<&str> = line.split_whitespace().collect();
-        left_list.push(parts[0].parse().unwrap());
-        right_list.push(parts[1].parse().unwrap());
-    }
+    let (mut left_list, mut right_list): (Vec<i32>, Vec<i32>) = input
+        .lines()
+        .map(|line| {
+            line.split_whitespace()
+                .map(|num| num.parse().expect("should be a number"))
+                .collect::<Vec<i32>>()
+        })
+        .map(|parts| (parts[0], parts[1]))
+        .unzip();
     left_list.sort();
     right_list.sort();
-    let mut sum = 0;
-    for (left, right) in left_list.iter().zip(right_list.iter()) {
-        sum += (left - right).abs();
-    }
-
-    sum
+    left_list
+        .iter()
+        .zip(right_list.iter())
+        .map(|(left, right)| (left - right).abs())
+        .sum()
 }
 
 pub fn part_b(input: &str) -> i32 {
-    let mut left_list: Vec<i32> = Vec::new();
-    let mut right_list: Vec<i32> = Vec::new();
-    for line in input.lines() {
-        let parts: Vec<&str> = line.split_whitespace().collect();
-        left_list.push(parts[0].parse().unwrap());
-        right_list.push(parts[1].parse().unwrap());
-    }
-    left_list.sort();
-    right_list.sort();
-    let mut sum = 0;
-    for left in left_list.iter() {
-        let mut count = 0;
-        for right in right_list.iter() {
-            if left == right {
-                count += 1;
-            }
-        }
-        sum += left * count;
+    let (left_list, right_list): (Vec<i32>, Vec<i32>) = input
+        .lines()
+        .map(|line| {
+            let parts: Vec<i32> = line
+                .split_whitespace()
+                .map(|num| num.parse().expect("should be a number"))
+                .collect();
+            (parts[0], parts[1])
+        })
+        .unzip();
+    let mut right_count = std::collections::HashMap::new();
+    for right in right_list {
+        *right_count.entry(right).or_insert(0) += 1;
     }
-
-    sum
+    left_list
+        .iter()
+        .map(|left| left * right_count.get(left).unwrap_or(&0))
+        .sum()
 }
 
 pub fn main() {
@@ -50,7 +48,31 @@ pub fn main() {
     println!("Day {} Example Part B: {}", day, part_b(example_input));
     println!("Day {} Part B: {}", day, part_b(input));
 }
+#[cfg(test)]
+mod tests {
+    use super::*;
 
-// #[cfg(test)]
-// mod tests {
-// }
+    #[test]
+    fn test_part_a_example() {
+        let example_input = include_str!("../input_example.txt");
+        assert_eq!(part_a(example_input), 11);
+    }
+
+    #[test]
+    fn test_part_a() {
+        let input = include_str!("../input.txt");
+        assert_eq!(part_a(input), 2113135);
+    }
+
+    #[test]
+    fn test_part_b_example() {
+        let example_input_b = include_str!("../input_example.txt");
+        assert_eq!(part_b(example_input_b), 31);
+    }
+
+    #[test]
+    fn test_part_b() {
+        let input = include_str!("../input.txt");
+        assert_eq!(part_b(input), 19097157);
+    }
+}