Construct_Binary_Tree_from_PreorderAndInorder_Traversal.py

class Solution:
    def buildTree(self, preorder: List[int], inorder: List[int]) -> Optional[TreeNode]:
        if not preorder or not inorder :
            return None
        root=TreeNode(preorder[0])
        mid=inorder.index(preorder[0])
        root.left=self.buildTree(preorder[1:mid+1],inorder[:mid])
        root.right=self.buildTree(preorder[mid+1:],inorder[mid+1:])
        return root