diff --git a/aoc2018/src/day05.rs b/aoc2018/src/day05.rs
index 9b2c52a..1b6ac4a 100644
--- a/aoc2018/src/day05.rs
+++ b/aoc2018/src/day05.rs
@@ -14,12 +14,11 @@ pub fn run() -> Result<String> {
     Ok(res)
 }
 
-fn same_type(a: char, b: char) -> bool {
-    a.to_ascii_lowercase() == b.to_ascii_lowercase()
-}
-
 fn remove_type(input: &str, c: char) -> String {
-    input.chars().filter(|ch| !same_type(c, *ch)).collect()
+    input
+        .chars()
+        .filter(|ch| !c.eq_ignore_ascii_case(ch))
+        .collect()
 }
 
 fn collapse(input: &str) -> String {
@@ -32,7 +31,7 @@ fn collapse(input: &str) -> String {
         match last {
             Some(elem) => {
                 // if same type but different polarity
-                if same_type(elem, next) && elem != next {
+                if elem.eq_ignore_ascii_case(&next) && elem != next {
                     // drop both elem and next
                     last = res.pop();
                 } else {
diff --git a/aoc2019/src/day14.rs b/aoc2019/src/day14.rs
index 4462914..5c7fb25 100644
--- a/aoc2019/src/day14.rs
+++ b/aoc2019/src/day14.rs
@@ -78,7 +78,7 @@ fn get_ore_cost(
             .with_context(|| format!("couldn't find recipe for {}", material))?;
 
         let needed = quantity - in_stock;
-        let num_reactions = (needed + recipe.produced - 1) / recipe.produced;
+        let num_reactions = needed.div_ceil(recipe.produced);
         for elem in &recipe.elems {
             total += get_ore_cost(
                 elem.name.clone(),
diff --git a/aoc2020/src/day07.rs b/aoc2020/src/day07.rs
index b846d51..22915af 100644
--- a/aoc2020/src/day07.rs
+++ b/aoc2020/src/day07.rs
@@ -70,7 +70,7 @@ impl BagRule {
         all_bags: &HashMap<String, BagRule>,
         memoized: &mut HashMap<String, bool>,
     ) -> bool {
-        return match memoized.get(&self.color) {
+        match memoized.get(&self.color) {
             Some(value) => *value,
             None => {
                 let value = self.contains.iter().any(|(_, c)| c == color)
@@ -85,7 +85,7 @@ impl BagRule {
 
                 value
             }
-        };
+        }
     }
 
     fn num_inner_bags(&self, all_bags: &HashMap<String, BagRule>) -> usize {
diff --git a/aoc2020/src/day13.rs b/aoc2020/src/day13.rs
index 5fe9974..8a36cb2 100644
--- a/aoc2020/src/day13.rs
+++ b/aoc2020/src/day13.rs
@@ -91,7 +91,7 @@ fn find_timestamp(input: &str) -> Result<u64> {
 }
 
 fn satisfies_constraint(solution: u64, (remainder, divisor): (u64, u64)) -> bool {
-    ((solution + remainder) % divisor) == 0
+    (solution + remainder).is_multiple_of(divisor)
 }
 
 #[cfg(test)]
diff --git a/aoc2021/src/day03.rs b/aoc2021/src/day03.rs
index a96113c..e4aa948 100644
--- a/aoc2021/src/day03.rs
+++ b/aoc2021/src/day03.rs
@@ -84,7 +84,7 @@ where
             break;
         }
 
-        let one_is_more_common = count_ones(&numbers, pos) >= ((numbers.len() + 1) / 2);
+        let one_is_more_common = count_ones(&numbers, pos) >= numbers.len().div_ceil(2);
         let digit_of_interest = strat(one_is_more_common);
 
         numbers.retain(|number| number.chars().nth(pos).unwrap() == digit_of_interest);
diff --git a/aoc2022/src/day03.rs b/aoc2022/src/day03.rs
index 1270cfa..a58b5dd 100644
--- a/aoc2022/src/day03.rs
+++ b/aoc2022/src/day03.rs
@@ -84,7 +84,7 @@ impl std::str::FromStr for RucksackSplit {
     type Err = anyhow::Error;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        if s.len() % 2 != 0 {
+        if !s.len().is_multiple_of(2) {
             bail!(
                 "rucksack should contain an even number of items, this one contained {}",
                 s.len()
diff --git a/aoc2023/src/day01.rs b/aoc2023/src/day01.rs
index 3152fb1..4e0fb86 100644
--- a/aoc2023/src/day01.rs
+++ b/aoc2023/src/day01.rs
@@ -28,7 +28,7 @@ fn part1(input: &str) -> Result<u64> {
         .sum())
 }
 
-fn part2(input: &str) -> Result<u64> {
+fn part2(_input: &str) -> Result<u64> {
     todo!()
 }