Don't need a Pair type for keyed ordering

Author: ejmount

src/k_smallest.rs

@@ -79,10 +79,10 @@ where
     F: Fn(&T) -> K,
     K: Ord,
 {
-    let iter = iter.map(|v| Pair(key(&v), v));
+    let iter = iter.map(|v| (key(&v), v));
 
-    let results: Vec<_> = k_smallest_general(iter, k, Ord::cmp)
-        .map(|Pair(_, t)| t)
+    let results: Vec<_> = k_smallest_general(iter, k, |(k, _), (l, _)| k.cmp(&l))
+        .map(|(_, t)| t)
         .collect();
     results.into_iter()
 }
@@ -120,21 +120,3 @@ fn sift_down<T>(
         }
     }
 }
-
-struct Pair<K, T>(K, T);
-impl<K: Ord, T> PartialEq for Pair<K, T> {
-    fn eq(&self, other: &Self) -> bool {
-        self.0 == other.0
-    }
-}
-impl<K: Ord, T> Eq for Pair<K, T> {}
-impl<K: Ord, T> PartialOrd for Pair<K, T> {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        self.0.partial_cmp(&other.0)
-    }
-}
-impl<K: Ord, T> Ord for Pair<K, T> {
-    fn cmp(&self, other: &Self) -> Ordering {
-        self.0.cmp(&other.0)
-    }
-}