106. Construct Binary Tree from Inorder and Postorder Traversal

https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal

Python

Study only try

Not self solution, the answer from here

class Solution:
    def buildTree(self, inorder, postorder):
        """
        :type inorder: List[int]
        :type postorder: List[int]
        :rtype: TreeNode
        """
        if not inorder or not postorder:
            return None
        root = postorder[-1]
        index = inorder.index(root)
        ret = TreeNode(postorder.pop())
        ret.right = self.buildTree(inorder[index+1:], postorder)
        ret.left = self.buildTree(inorder[:index], postorder)
        return ret

Second try

Solution which more Pythonic

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

        root_val = postorder[-1]
        root_index = inorder.index(root_val)

        return TreeNode(
            val=root_val,
            left=self.buildTree(
                inorder[:root_index],
                postorder[:root_index]
            ),
            right=self.buildTree(
                inorder[root_index+1:],
                postorder[root_index:-1]
            )
        )