diff --git a/src/ds/frequency_buckets.rs b/src/ds/frequency_buckets.rs
index 2db4117..f7c1a86 100644
--- a/src/ds/frequency_buckets.rs
+++ b/src/ds/frequency_buckets.rs
@@ -1230,10 +1230,10 @@ where
         let mut prev = None;
         let mut next = None;
         for &f in self.buckets.keys() {
-            if f < freq && prev.is_none_or(|p| f > p) {
+            if f < freq && prev.map_or(true, |p| f > p) {
                 prev = Some(f);
             }
-            if f > freq && next.is_none_or(|n| f < n) {
+            if f > freq && next.map_or(true, |n| f < n) {
                 next = Some(f);
             }
         }
@@ -2013,7 +2013,7 @@ where
             let Some(freq) = buckets.min_freq() else {
                 continue;
             };
-            let is_better = best.is_none_or(|(_, best_freq)| freq < best_freq);
+            let is_better = best.map_or(true, |(_, best_freq)| freq < best_freq);
             if is_better {
                 best = Some((idx, freq));
             }
@@ -2051,7 +2051,7 @@ where
             let Some(freq) = buckets.min_freq() else {
                 continue;
             };
-            let is_better = best.is_none_or(|(_, best_freq)| freq < best_freq);
+            let is_better = best.map_or(true, |(_, best_freq)| freq < best_freq);
             if is_better {
                 best = Some((idx, freq));
             }