curriculum/challenges/english/blocks/learn-tree-traversal-by-building-a-binary-search-tree/65ca06864129380054b55dc0.md
Within the if block, replace pass with a call to the _delete method, passing the left child of the current node and the key as arguments. Assign the function call to the left node.
You should remove the pass keyword from the if statement.
({
test: () => {
assert.isFalse(
runPython(
`_Node(_code).find_class("BinarySearchTree").find_function("_delete").find_if("key < node.key").find_bodies()[0].has_pass()`
)
);
},
});
You should call the _delete method with node.left and the key as the arguments.
assert.match(code, /self\._delete\(\s*node\.left\s*,\s*key\s*\)/);
You should assign the result of the _delete() call to the left child (node.left) of the current node.
assert.match(code, /node\.left\s*=\s*self\._delete\(\s*node\.left\s*,\s*key\s*\)/);
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):
if node is None:
return node
if key < 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))