Add heapify function to binary heap

src/backing/pure/binary_heap.rs

@@ -103,6 +103,18 @@ impl<T: Ord + Copy> BinaryHeap<T> {
     }
 }
 
+impl<T: Ord + Copy> FromIterator<T> for BinaryHeap<T> {
+    fn from_iter<U: IntoIterator<Item = T>>(iter: U) -> Self {
+        let mut this = Self {
+            data: Vec::from_iter(iter),
+        };
+        for i in (0..=(this.data.len() / 2)).rev() {
+            this.sift_down(i);
+        }
+        this
+    }
+}
+
 impl<T: Ord + Copy> PureBacking<T> for BinaryHeap<T> {
     fn new() -> Self {
         Self { data: vec![] }