Add feature get_parent_node

binarytree/__init__.py

@@ -14,7 +14,6 @@
     NodeModifyError,
     NodeNotFoundError,
     NodeReferenceError,
-    WtreeUnsetError,
 )
 
 
@@ -315,7 +314,7 @@ def _get_tree_properties(root):
     }
 
 
-def _get_parent_node(root, node):
+def get_parent_node(root, node):
     """Search from the binary tree and return the parent node for require node.
 
     :param root: Root node of the binary tree.
@@ -324,27 +323,46 @@ def _get_parent_node(root, node):
     :rtype: binarytree.Node
     :return: The parent node of require node.
     :rtype: binarytree.Node
+
+    **Example**:
+
+        .. doctest::
+
+            >>> from binarytree import Node, get_parent_node
+            >>> root = Node(0)
+            >>> root.left = Node(1)
+            >>> root.right = Node(2)
+            >>> root.left.left = Node(3)
+            >>> print (root)
+            >>>     0
+                   / \
+                  1   2
+                 /
+                3
+            >>> print (get_parent_node(root, root.left.left))
+            >>>   1
+                 /
+                3
     """
-    root_height = root.height
-    node_height = node.height
-    if root_height == node_height:
+    if root is node or root is None or node is None:
         return None
-    node_level_list = root.levels[root_height - node_height]
-    parent_level_list = root.levels[root_height - node_height - 1]
-    node_index = 0
-    for index in range(len(node_level_list)):
-        if node_level_list[index].value == node.value:
-            node_index = index
+    node_stack = []
+    while True:
+        if root is not None:
+            node_stack.append(root)
+            if root.left is node:
+                return root
+            else:
+                root = root.left
+        elif len(node_stack) > 0:
+            root = node_stack.pop()
+            if root.right is node:
+                return root
+            else:
+                root = root.right
+        else:
             break
-    start_index = node_index // 2
-    for pnode in parent_level_list[start_index:]:
-        try:
-            if pnode.left.value == node.value or\
-                                pnode.right.value == node.value:
-                return pnode
-        except AttributeError:
-            raise WtreeUnsetError('You should set a tree for the node\
-                                  you want')
+    return None
 
 
 class Node(object):
@@ -1064,57 +1082,6 @@ def size(self):
         """
         return _get_tree_properties(self)['size']
 
-    @property
-    def wtree(self):
-        """Set the input tree as a search space.
-        """
-        return self._root
-
-    @wtree.setter
-    def wtree(self, tree):
-        """The setter function for wtree setting.
-
-        :param tree: The start root node of the binary tree.
-        :rtype: binarytree.Node
-        """
-        self._root = tree
-
-    @property
-    def upper(self):
-        """Get the parent node from a given tree.
-
-        :param tree: The start root node of the binary tree.
-        :rtype: binarytree.Node
-        :return: The parent node for this node.
-        :rtype: binarytree.Node
-
-        **Example**:
-
-        .. doctest::
-
-            >>> from binarytree import Node
-            >>> root = Node(0)
-            >>> root.left = Node(1)
-            >>> root.right = Node(2)
-            >>> root.left.left = Node(3)
-            >>> print (root)
-            >>>     0
-                   / \
-                  1   2
-                 /
-                3
-            >>> root.left.left.wtree = root
-            >>> print (root.left.left.upper)
-            >>>   1
-                 /
-                3
-        """
-        try:
-            return _get_parent_node(self._root, self)
-        except AttributeError:
-            raise WtreeUnsetError('You should set a tree for the node you want\
-                                  to search.')
-
     @property
     def leaf_count(self):
         """Return the total number of leaf nodes in the binary tree.

binarytree/exceptions.py

@@ -31,7 +31,3 @@ class NodeValueError(BinaryTreeError):
 
 class TreeHeightError(BinaryTreeError):
     """Tree height was invalid."""
-
-
-class WtreeUnsetError(BinaryTreeError):
-    """The whole tree was unset."""

tests/test_tree.py

@@ -6,7 +6,7 @@
 import pytest
 
 from binarytree import Node, build, tree, bst, heap
-from binarytree import _get_parent_node
+from binarytree import get_parent_node
 from binarytree.exceptions import (
     NodeValueError,
     NodeIndexError,
@@ -15,7 +15,6 @@
     NodeNotFoundError,
     TreeHeightError,
     NodeReferenceError,
-    WtreeUnsetError,
 )
 from tests.utils import (
     builtin_print,
@@ -887,23 +886,15 @@ def test_heap_float_values():
 
 
 @pytest.mark.order14
-def test_get_upper_node():
+def test_get_parent_node():
     root = Node(0)
     root.left = Node(1)
     root.right = Node(2)
     root.left.left = Node(3)
-    root.left.left.wtree = root
-    assert root.left.left.upper == root.left
-    root.left.left.upper.wtree = root
-    assert root.left.left.upper.upper == root
-    root.wtree = root
-    assert root.upper is None
-    with pytest.raises(WtreeUnsetError) as err:
-        root = root.right.upper
-        assert str(err.value) == 'You should set a tree for the node you want'
-    with pytest.raises(WtreeUnsetError) as err:
-        root = _get_parent_node(root, root.right)
-        assert str(err.value) == 'You should set a tree for the node you want'
-    root.right.wtree = root
-    assert root.right._root == root
-    assert root.right.wtree == root
+    root.right.right = Node(4)
+    assert get_parent_node(root, root.left.left) == root.left
+    assert get_parent_node(root, root.left) == root
+    assert get_parent_node(root, root) is None
+    assert get_parent_node(root, root.right.right) == root.right
+    assert get_parent_node(root, root.right) == root
+    assert get_parent_node(root, Node(5)) is None