题解 | #二叉树的中序遍历#

class Solution:
    def inorderTraversal(self , root: TreeNode) -> List[int]:
        ans = []
        def inorder(root):
            if not root: return
            if root.left:
                inorder(root.left)
            ans.append(root.val)
            if root.right:
                inorder(root.right)
        inorder(root)
        return ans