diff --git a/src/day1.rs b/src/day1.rs
index 6510021..fc20e33 100644
--- a/src/day1.rs
+++ b/src/day1.rs
@@ -1,12 +1,12 @@
 use std::io::{self, BufRead};
 
-fn increases(measurements: &Vec<u64>) -> u64 {
+fn increases(measurements: &[u64]) -> u64 {
     measurements
         .windows(2)
         .fold(0, |acc, x| if x[1] > x[0] { acc + 1 } else { acc })
 }
 
-fn convolve(measurements: &Vec<u64>) -> Vec<u64> {
+fn convolve(measurements: &[u64]) -> Vec<u64> {
     measurements.windows(3).map(|x| x.iter().sum()).collect()
 }
 
diff --git a/src/day3.rs b/src/day3.rs
index 18c15d6..a3281a1 100644
--- a/src/day3.rs
+++ b/src/day3.rs
@@ -21,7 +21,7 @@ impl<const N: usize> Diagnostics<N> {
         u32::from_str_radix(&self.least_common_value(), 2).unwrap()
     }
 
-    fn count_bit(&self, values: &Vec<String>, bit: usize) -> (usize, usize) {
+    fn count_bit(&self, values: &[String], bit: usize) -> (usize, usize) {
         values
             .iter()
             .fold((0, 0), |acc, x| match x.chars().nth(bit).unwrap() {
diff --git a/src/day4.rs b/src/day4.rs
index 3159ded..82b55f1 100644
--- a/src/day4.rs
+++ b/src/day4.rs
@@ -11,13 +11,10 @@ struct Board {
 }
 
 impl Board {
-    fn mark<'a>(&'a mut self, number: u8) {
+    fn mark(&mut self, number: u8) {
         for row in self.grid.iter_mut() {
-            match row.iter_mut().find(|square| square.number == number) {
-                Some(square) => {
-                    square.marked = true;
-                }
-                None => {}
+            if let Some(square) = row.iter_mut().find(|square| square.number == number) {
+                square.marked = true;
             }
         }
     }