add python 701 and python 173

python-leetcode/README.md

@@ -47,6 +47,8 @@
 33. [祖父节点值为偶数的节点和](./solution/tree/leetcode_1315_.py)
 34. [两棵二叉搜索树中的所有元素](./solution/tree/leetcode_1305_.py)
 35. [二叉树剪枝](./solution/tree/leetcode_814_.py)
+36. [二叉搜索树中的插入操作](./solution/tree/leetcode_701_.py)
+37. [二叉搜索树迭代器](./solution/tree/leetcode_173_.py)
 
 
 

python-leetcode/solution/tree/leetcode_173_.py

+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# coding=utf-8
+"""
+173. 二叉搜索树迭代器
+"""
+from solution import TreeNode
+
+
+class BSTIterator:
+    list = []
+
+    def __init__(self, root: TreeNode):
+        while root:
+            self.list.append(root)
+            root = root.left
+
+    def next(self) -> int:
+        """
+        @return the next smallest number
+        """
+        node = self.list.pop()
+        t = node.right
+        while (t):
+            self.list.append(t)
+            t = t.left
+
+        return node.val
+
+    def hasNext(self) -> bool:
+        """
+        @return whether we have a next smallest number
+        """
+        return len(self.list) != 0

python-leetcode/solution/tree/leetcode_701_.py

+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# coding=utf-8
+"""
+701. 二叉搜索树中的插入操作
+"""
+from solution import TreeNode
+
+
+class Solution:
+    def insertIntoBST(self, root: TreeNode, val: int) -> TreeNode:
+        if not root:
+            return TreeNode(val)
+        if root.val >= val:
+            root.left = self.insertIntoBST(root.left, val)
+        else:
+            root.right = self.insertIntoBST(root.right, val)
+
+        return root
+
+        helper(root)
+        return res