python中序遍历二叉树

以下是Python中序遍历二叉树的两种实现方法：

1. 递归实现：

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

2. 显式栈实现：

class Solution:
    def inorderTraversal(self, root: TreeNode) -> List[int]:
        res = []
        stack = []
        curr = root
        
        while curr or stack:
            while curr:
                stack.append(curr)
                curr = curr.left
            curr = stack.pop()
            res.append(curr.val)
            curr = curr.right
        
        return res