solves trim a binary search tree

Author: anishLearnsToCode

README.md

@@ -172,7 +172,7 @@
 | 657 | [Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin) | [![Java](assets/java.png)](src/RobotReturnToOrigin.java) [![Python](assets/python.png)](python/robot_return_to_origin.py) |
 | 661 | [Image Smoother](https://leetcode.com/problems/image-smoother) | [![Java](assets/java.png)](src/ImageSmoother.java) [![Python](assets/python.png)](python/image_smoother.py) |
 | 665 | [Non Deceasing Array](https://leetcode.com/problems/non-decreasing-array) | [![Java](assets/java.png)](src/NonDecreasingArray.java) [![Python](assets/python.png)](python/non_decreasing_array.py) |
-| 669 | [Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree) | |
+| 669 | [Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree) | [![Java](assets/java.png)](src/TrimABinarySearchTree.java) [![Python](assets/python.png)](python/trim_a_binary_search_tree.py) |
 | 671 | [Second Minimum Node in Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree) | |
 | 674 | [Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence) | |
 | 680 | [Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii) | |

python/trim_a_binary_search_tree.py

@@ -0,0 +1,16 @@
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class Solution:
+    def trimBST(self, root: TreeNode, low: int, high: int) -> TreeNode:
+        if root is None: return None
+        if root.val < low: return self.trimBST(root.right, low, high)
+        if root.val > high: return self.trimBST(root.left, low, high)
+        root.left = self.trimBST(root.left, low, high)
+        root.right = self.trimBST(root.right, low, high)
+        return root

src/TrimABinarySearchTree.java

@@ -0,0 +1,10 @@
+public class TrimABinarySearchTree {
+    public TreeNode trimBST(TreeNode root, int low, int high) {
+        if (root == null) return null;
+        if (root.val < low) return trimBST(root.right, low, high);
+        if (root.val > high) return trimBST(root.left, low, high);
+        root.left = trimBST(root.left, low, high);
+        root.right = trimBST(root.right, low, high);
+        return root;
+    }
+}