diff --git a/rust/src/day04/part_1.rs b/rust/src/day04/part_1.rs
index e9f5ddd..d9b0915 100644
--- a/rust/src/day04/part_1.rs
+++ b/rust/src/day04/part_1.rs
@@ -12,8 +12,7 @@ pub(crate) fn part_1(input: &[[[u32; 2]; 2]]) -> usize {
     let times_contained = input
         .iter()
         .filter(|sections| sections_contain_each_other(**sections))
-        .collect::<Vec<_>>()
-        .len();
+        .count();
     println!("Part 1: {times_contained}");
     times_contained
 }
diff --git a/rust/src/day04/part_2.rs b/rust/src/day04/part_2.rs
index 8fa20da..b40e8b0 100644
--- a/rust/src/day04/part_2.rs
+++ b/rust/src/day04/part_2.rs
@@ -12,8 +12,7 @@ pub(crate) fn part_2(input: &[[[u32; 2]; 2]]) -> usize {
     let times_overlapped = input
         .iter()
         .filter(|sections| sections_overlap(**sections))
-        .collect::<Vec<_>>()
-        .len();
+        .count();
     println!("Part 2: {times_overlapped}");
     times_overlapped
 }
diff --git a/rust/src/day09/part_1.rs b/rust/src/day09/part_1.rs
index f749a63..2689923 100644
--- a/rust/src/day09/part_1.rs
+++ b/rust/src/day09/part_1.rs
@@ -2,7 +2,7 @@ use std::collections::HashSet;
 
 use crate::Move;
 
-pub(crate) fn part_1(input: &Vec<Move>) -> usize {
+pub(crate) fn part_1(input: &[Move]) -> usize {
     let mut head_position = (0i64, 0i64);
     let mut tail_position = (0i64, 0i64);
     let mut visited_tail_positions = HashSet::new();
diff --git a/rust/src/day09/part_2.rs b/rust/src/day09/part_2.rs
index e5eaecf..5afab14 100644
--- a/rust/src/day09/part_2.rs
+++ b/rust/src/day09/part_2.rs
@@ -52,7 +52,7 @@ fn tail_update(diff: (i64, i64)) -> (i64, i64) {
     }
 }
 
-pub(crate) fn part_2(input: &Vec<Move>) -> usize {
+pub(crate) fn part_2(input: &[Move]) -> usize {
     let mut rope = Rope::<TAIL_LENGTH>::new();
 
     for head_movement in input {