diff --git a/data_structures/arrays/two_sum.rb b/data_structures/arrays/two_sum.rb
index efc8fd6..318ee7f 100644
--- a/data_structures/arrays/two_sum.rb
+++ b/data_structures/arrays/two_sum.rb
@@ -26,7 +26,10 @@
 # 
 # Approach 1: Brute Force with Addition
 #
-# Time Complexity: O(N^2), where N is the length of the array
+# Time Complexity: O(n^2). For each element, we try to find its complement
+# by looping through the rest of the array which takes O(n) time.
+# Therefore, the time complexity is O(n^2)
+# Space complexity: O(1)
 #
 def two_sum(nums, target)
   result_array = []