[inorderBST]using yield and yiled from #Python #Algorithm

inorder_BST.py

class Solution:
    def increasingBST(self, root):
        def inorder(node):
            if node:
              	# 这里用了yield 和 yield from
                # yield from 作为递归
                # yield 返回值
                # 这是一个左中右的 inorder 遍历
                # 返回一个 generator
                yield from inorder(node.left)
                yield node.val
                yield from inorder(node.right)

        ans = cur = TreeNode(None)
        for v in inorder(root):
            cur.right = TreeNode(v)
            cur = cur.right
        return ans.right