update readme

Author: sagivo

README.md

@@ -13,7 +13,7 @@ This is my way of saying - change your interview style. There are lots of smart
 
 | problem | solution |
 |-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| [Unique binary search trees](https://leetcode.com/problems/unique-binary-search-trees/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/house-robber.rb) |
+| [Unique binary search trees](https://leetcode.com/problems/unique-binary-search-trees/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/unique_bst.rb) |
 | [House Robber](https://leetcode.com/problems/house-robber/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/house-robber.rb) |
 | [Array Product](https://leetcode.com/problems/product-of-array-except-self/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/product-of-array.rb) |
 | [Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/description/) | [click](https://github.com/sagivo/algorithms/blob/master/src/top-k-elements.rb) |