Implemented linear and binary search with tests.

Searches/binary_search.rb

@@ -0,0 +1,23 @@
+=begin
+Searches through a list for a value in O(log(n)) time.
+The list must be sorted.
+=end
+def binary_search(array, key)
+  front = 0
+  back = array.length - 1
+  while front <= back
+    middle = (front + back) / 2
+    return middle if array[middle] == key
+    key < array[middle] ?
+      back = middle - 1 : front = middle + 1
+  end
+  nil
+end
+
+puts "Enter a sorted space-separated list:"
+arr = gets.chomp.split(' ').map(&:to_i)
+puts "Enter the value to be searched:"
+value = gets.chomp.to_i
+puts binary_search(arr, value) != nil ?
+  "Found at index #{binary_search(arr, value)}" :
+  "Not found"

Searches/linear_search.rb

@@ -0,0 +1,18 @@
+=begin
+Looks through array for a value in O(n) time.
+Array does not need to be sorted.
+=end
+def linear_search(array, key)
+  array.each_with_index do |current, index|
+    return index if current == key
+  end
+  return nil
+end
+
+puts "Enter a space-separated list:"
+arr = gets.chomp.split(' ').map(&:to_i)
+puts "Enter a value to be searched:"
+key = gets.chomp.to_i
+puts linear_search(arr, key) != nil ?
+  "Found at index #{linear_search(arr, key)}" :
+  "Not found"