curriculum/challenges/english/blocks/learn-tree-traversal-by-building-a-binary-search-tree/65ca05f7cba1e6fe70527534.md
Inside your _delete method, replace pass with an if statement that checks if the current node is None.
When the current node is None, the key to be deleted was not found. Therefore, return node from your if block.
You should remove the pass keyword from the _delete method.
({
test: () => {
assert.isFalse(
runPython(
`_Node(_code).find_class("BinarySearchTree").find_function("_delete").has_pass()`
)
);
},
});
You should write an if statement that checks if the current node is None.
const after_split = code.split('def _delete(self, node, key):')[1];
assert.match(after_split, /if\s+node\s+is\s+None/);
You should return node inside your if block.
const after_split = code.split('def _delete(self, node, key):')[1];
assert.match(after_split, /return\s+node/);
class TreeNode:
def __init__(self, key):
self.key = key
self.left = None
self.right = None
def __str__(self):
return str(self.key)
class BinarySearchTree:
def __init__(self):
self.root = None
def _insert(self, node, key):
if node is None:
return TreeNode(key)
if key < node.key:
node.left = self._insert(node.left, key)
elif key > node.key:
node.right = self._insert(node.right, key)
return node
def insert(self, key):
self.root = self._insert(self.root, key)
def _search(self, node, key):
if node is None or node.key == key:
return node
if key < node.key:
return self._search(node.left, key)
return self._search(node.right, key)
def search(self, key):
return self._search(self.root, key)
--fcc-editable-region--
def _delete(self, node, key):
pass
--fcc-editable-region--
bst = BinarySearchTree()
nodes = [50, 30, 20, 40, 70, 60, 80]
for node in nodes:
bst.insert(node)
# print('Search for 80:', bst.search(80))