Learn Tree Traversal by Building a Binary Search Tree - Step 46

Tell us what’s happening:

I’m stuck on this step. What am I missing?

Call the _delete method recursively with node.right and node.key as the arguments. Assign the return value of the _delete() call to the right child of the current node.

Your code so far


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)


# User Editable Region

    def _delete(self, node, key):
        if node is None:
            return node
        if key < node.key:
            node.left = self._delete(node.left, key)
        elif key > node.key:
            node.right = self._delete(node.right, key)
        else:
            if node.left is None:
                return node.right
            elif node.right is None:
                return node.left

            node.key = self._min_value(node.right) 
            node.right = return self_delete(node.right,node.key)    

# User Editable Region

    def _min_value(self, node):
        while node.left is not None:
            node = node.left

bst = BinarySearchTree()

nodes = [50, 30, 20, 40, 70, 60, 80]

for node in nodes:
    bst.insert(node)

# print('Search for 80:', bst.search(80))


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Challenge Information:

Learn Tree Traversal by Building a Binary Search Tree - Step 46

Hi @Mikie22

You have a syntax error.

Try removing the invalid syntax.

Hint: take a look at how the code on the line above 57 is structured

Happy coding

Thank you very much!

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