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curriculum/challenges/english/blocks/learn-tree-traversal-by-building-a-binary-search-tree/65f97131a0709033d6911558.md

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--description--

Create a list named nodes with values 50, 30, 20, 40, 70, 60, 80.

--hints--

Your list should have the values 50, 30, 20, 40, 70, 60, 80.

js
assert.match(code, /\s*\[50,\s*30,\s*20,\s*40,\s*70,\s*60,\s*80\]/);

Your list should be assigned to nodes.

js
assert.match(code, /nodes\s*=\s*\[50,\s*30,\s*20,\s*40,\s*70,\s*60,\s*80\]/);

--seed--

--seed-contents--

py

class TreeNode:

    def __init__(self, key):
        self.key = key
        self.left = None
        self.right = None


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--
bst = BinarySearchTree()


--fcc-editable-region--