From 1582d072593cd2fc8abed038ff21e9666f990804 Mon Sep 17 00:00:00 2001
From: Kyle Lim <kylelim8998@gmail.com>
Date: Sat, 5 Oct 2019 02:37:35 -0400
Subject: [PATCH] Solution of 669

---
 600-700q/669.py | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 README.md       |  1 +
 2 files changed, 56 insertions(+)
 create mode 100644 600-700q/669.py

diff --git a/600-700q/669.py b/600-700q/669.py
new file mode 100644
index 0000000..7298f04
--- /dev/null
+++ b/600-700q/669.py
@@ -0,0 +1,55 @@
+'''
+Given a binary search tree and the lowest and highest boundaries as L and R, trim the tree so that all its elements lies in [L, R] (R >= L). You might need to change the root of the tree, so the result should return the new root of the trimmed binary search tree.
+
+Example 1:
+Input: 
+    1
+   / \
+  0   2
+
+  L = 1
+  R = 2
+
+Output: 
+    1
+      \
+       2
+Example 2:
+Input: 
+    3
+   / \
+  0   4
+   \
+    2
+   /
+  1
+
+  L = 1
+  R = 3
+
+Output: 
+      3
+     / 
+   2   
+  /
+ 1
+'''
+
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def trimBST(self, root: TreeNode, L: int, R: int) -> TreeNode:
+        if not root:
+            return None
+        if L > root.val:
+            return self.trimBST(root.right, L, R)
+        elif R < root.val:
+            return self.trimBST(root.left, L, R)
+        root.left = self.trimBST(root.left, L, R)
+        root.right = self.trimBST(root.right, L, R)
+        return root
diff --git a/README.md b/README.md
index 9f03b51..9078ed0 100644
--- a/README.md
+++ b/README.md
@@ -120,6 +120,7 @@ Python solution of problems from [LeetCode](https://leetcode.com/).
 |681|[Next Closest Time ](https://leetcode.com/problems/next-closest-time)|[Python](./600-700q/681.py)|Medium|
 |674|[Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence)|[Python](./600-700/674.py)|Easy|
 |673|[Number of Longest Increasing Subsequence](https://leetcode.com/problems/number-of-longest-increasing-subsequence)|[Python](./600-700q/673.py)|Medium|
+|669|[Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree)|[Python](./600-700q/673.py)|Easy|
 
 
 ##### [Problems 400-500](./400-500Q/)