Merge pull request neetcode-gh#1871 from tahsintunan/669

Create 669. Trim a Binary Search Tree

go/0669-trim-a-binary-search-tree.go

@@ -0,0 +1,23 @@
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func trimBST(root *TreeNode, low int, high int) *TreeNode {
+	if root == nil {
+		return nil
+	}
+	if root.Val > high {
+		return trimBST(root.Left, low, high)
+	}
+	if root.Val < low {
+		return trimBST(root.Right, low, high)
+	}
+	root.Left = trimBST(root.Left, low, high)
+	root.Right = trimBST(root.Right, low, high)
+
+	return root
+}