Merge pull request #29 from shunsvineyard/bug_fix

Bug fix: delete on left threaded binary search tree.
burpeesDaily · Jul 10, 2021 · f6dfd27 · f6dfd27
2 parents 585e924 + 0fafb14
commit f6dfd27
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Showing 3 changed files with 37 additions and 11 deletions.
diff --git a/forest/binary_trees/single_threaded_binary_trees.py b/forest/binary_trees/single_threaded_binary_trees.py
@@ -582,17 +582,12 @@ def delete(self, key: Any) -> None:
             elif deleting_node.right and deleting_node.left:
                 replacing_node: Node = self.get_leftmost(node=deleting_node.right)
                 successor = self.get_successor(node=replacing_node)
-                # the minmum node is not the direct child of the deleting node
+                # the leftmost node is not the direct child of the deleting node
                 if replacing_node.parent != deleting_node:
-                    if replacing_node.is_thread:
-                        self._transplant(
-                            deleting_node=replacing_node, replacing_node=None
-                        )
-                    else:
-                        self._transplant(
-                            deleting_node=replacing_node,
-                            replacing_node=replacing_node.right,
-                        )
+                    self._transplant(
+                        deleting_node=replacing_node,
+                        replacing_node=replacing_node.right,
+                    )
                     replacing_node.right = deleting_node.right
                     replacing_node.right.parent = replacing_node
 

diff --git a/setup.py b/setup.py
@@ -12,7 +12,7 @@
 # This call to setup() does all the work
 setuptools.setup(
     name="forest-python",
-    version="0.5.2",
+    version="0.5.3",
     description="The Forest Project in Python",
     long_description=README,
     long_description_content_type="text/x-rst",

diff --git a/tests/test_single_threaded_binary_trees.py b/tests/test_single_threaded_binary_trees.py
@@ -256,3 +256,34 @@ def test_deletion_left_threaded_case(basic_tree):
         (4, "4"),
         (1, "1"),
     ] == [item for item in tree.reverse_inorder_traverse()]
+
+
+def test_deletion_left_threaded_case_2():
+    """Test the deletion of a left threaded binary tree."""
+    tree = single_threaded_binary_trees.LeftThreadedBinaryTree()
+
+    test_tree = [
+        (4, "4"),
+        (1, "1"),
+        (7, "7"),
+        (3, "3"),
+        (5, "5"),
+        (8, "8"),
+        (2, "2"),
+        (6, "6"),
+    ]
+
+    for key, data in test_tree:
+        tree.insert(key=key, data=data)
+
+    tree.delete(4)
+
+    assert [
+        (8, "8"),
+        (7, "7"),
+        (6, "6"),
+        (5, "5"),
+        (3, "3"),
+        (2, "2"),
+        (1, "1"),
+    ] == [item for item in tree.reverse_inorder_traverse()]