exercism-64 Binary-Search

Author: kumar91gopi

README.md

@@ -281,6 +281,7 @@ solution of many challenges of [Leetcode](https://leetcode.com/), [Exercism](htt
 61. [Bob](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/bob.rb)
 62. [Nth Prime](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/nth_prime.rb)
 63. [Perfect Numbers](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/perfect_numbers.rb)
+64. [Binary Search](https://github.com/kumar91gopi/Algorithms-and-Data-Structures-in-Ruby/blob/master/exercism/binary_search.rb)
 
 <a name="leetcode"/>
 

exercism/binary_search.rb

@@ -0,0 +1,19 @@
+# Problem: https://exercism.org/tracks/ruby/exercises/binary-search
+
+# Solution
+class BinarySearch
+    def initialize(playlist)
+      @playlist = playlist
+    end
+    
+    def search_for(song,left=0,right=@playlist.length-1)
+      return nil if left>right
+      mid = left+((right-left)/2)
+      return mid if @playlist[mid]==song
+      if @playlist[mid]>song
+        return search_for(song,left,mid-1)
+      else
+        return search_for(song,mid+1,right)
+      end
+    end
+end