def test_to_list_middle_leaves(self):
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
root.left.right = TreeNode(4)
root.right.left = TreeNode(5)
self.assertListEqual(to_list(root), [1, 2, 3, None, 4, 5])
def pruneTree(self, root: TreeNode) -> TreeNode:
"""
prune the tree recursively!
"""
if root is None:
return None
if root.left is not None:
root.left = self.pruneTree(root.left)
if root.right is not None:
root.right = self.pruneTree(root.right)
if root.left is None and root.right is None:
if root.val == 0:
return None
else:
return root
return root
def test_to_list_both_children(self):
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
self.assertListEqual(to_list(root), [1, 2, 3])
def test_to_list_missing_right(self):
root = TreeNode(1)
root.left = TreeNode(2)
self.assertListEqual(to_list(root), [1, 2])
