这个题没啥好说的 easy

WechatIMG25.jpeg

class Solution:
    def buildTree(self, preorder: List[int], inorder: List[int]) -> TreeNode:
        if not preorder or not inorder:
            return None

        val = preorder[0]
        root = TreeNode(val)
        index = inorder.index(val)
        
        left = self.buildTree(preorder[1:index+1], inorder[:index])
        right = self.buildTree(preorder[index+1:], inorder[index+1:])

        root.left = left
        root.right = right

        return root