diff --git a/src/graph/lowest_common_ancestor.rs b/src/graph/lowest_common_ancestor.rs
index 2485f9cb216..60fa3ff13ca 100644
--- a/src/graph/lowest_common_ancestor.rs
+++ b/src/graph/lowest_common_ancestor.rs
@@ -205,7 +205,7 @@ mod tests {
             }
         }
         let mut offline_answers = offline.answer_queries(1, &tree);
-        offline_answers.sort_unstable_by(|a1, a2| a1.query_id.cmp(&a2.query_id));
+        offline_answers.sort_unstable_by_key(|a| a.query_id);
         assert_eq!(offline_answers, online_answers);
     }
 }
diff --git a/src/greedy/job_sequencing.rs b/src/greedy/job_sequencing.rs
index 54133e4ae1f..6b45e4d33cd 100644
--- a/src/greedy/job_sequencing.rs
+++ b/src/greedy/job_sequencing.rs
@@ -85,7 +85,7 @@ pub fn schedule_jobs(mut jobs: Vec<Job>) -> ScheduleResult {
     }
 
     // Step 1 – sort jobs by profit, highest first.
-    jobs.sort_unstable_by(|a, b| b.profit.cmp(&a.profit));
+    jobs.sort_unstable_by_key(|a| std::cmp::Reverse(a.profit));
 
     // Step 2 – allocate slots.
     // At most n jobs can ever be scheduled, so cap the slot count at jobs.len()
diff --git a/src/string/burrows_wheeler_transform.rs b/src/string/burrows_wheeler_transform.rs
index 3ecef7b9ab3..071b16e9f56 100644
--- a/src/string/burrows_wheeler_transform.rs
+++ b/src/string/burrows_wheeler_transform.rs
@@ -26,7 +26,7 @@ pub fn inv_burrows_wheeler_transform<T: AsRef<str>>(input: (T, usize)) -> String
         table.push((i, input.0.as_ref().chars().nth(i).unwrap()));
     }
 
-    table.sort_by(|a, b| a.1.cmp(&b.1));
+    table.sort_by_key(|a| a.1);
 
     let mut decoded = String::new();
     let mut idx = input.1;
diff --git a/src/string/manacher.rs b/src/string/manacher.rs
index e45a3f15612..aa0a102533c 100644
--- a/src/string/manacher.rs
+++ b/src/string/manacher.rs
@@ -54,8 +54,7 @@ pub fn manacher(s: String) -> String {
         radius += 1;
         // 2: Checking palindrome.
         // Need to care about overflow usize.
-        while i >= radius && i + radius <= chars.len() - 1 && chars[i - radius] == chars[i + radius]
-        {
+        while i >= radius && i + radius < chars.len() && chars[i - radius] == chars[i + radius] {
             length_of_palindrome[i] += 2;
             radius += 1;
         }