Add default, is_empty

radix_tree/src/lib.rs

@@ -10,6 +10,7 @@ mod tests {
   fn initial_len_0() {
     let tree = RadixTree::<usize, 4>::new();
     assert_eq!(tree.len(), 0);
+    assert!(tree.is_empty());
   }
 
   #[test]
@@ -17,6 +18,7 @@ mod tests {
     let mut tree = RadixTree::<usize, 4>::new();
     tree.push(0);
     assert_eq!(tree.len(), 1);
+    assert!(!tree.is_empty());
   }
 
   #[test]

radix_tree/src/radix_tree.rs

@@ -20,6 +20,13 @@ impl<T: Clone, const N: usize> RadixTree<T, N> {
     RadixTree::<T, N>(Rc::new(RadixTreeData::<T, N>::Meta(ArrayVec::new())))
   }
 
+  pub fn is_empty(&self) -> bool {
+    match &*self.0 {
+      RadixTreeData::Meta(_) => false,
+      RadixTreeData::Leaves(leaves) => leaves.is_empty(),
+    }
+  }
+
   pub fn len(&self) -> usize {
     let mut res = 0;
     let mut tree = self;
@@ -137,3 +144,9 @@ impl<T: Clone, const N: usize> RadixTree<T, N> {
     meta_node_with_space.push(RadixTree(Rc::new(RadixTreeData::Leaves(new_leaves))));
   }
 }
+
+impl<T: Clone, const N: usize> Default for RadixTree<T, N> {
+  fn default() -> Self {
+    Self::new()
+  }
+}