missing number solution with complexities

Author: yhkee0404

missing-number/yhkee0404.scala

@@ -1,5 +1,5 @@
 object Solution {
     def missingNumber(nums: Array[Int]): Int = {
-        (1 to nums.length).reduce(_ ^ _) ^ nums.reduce(_ ^ _)
+        (1 to nums.length).reduce(_ ^ _) ^ nums.reduce(_ ^ _) // T(n) = O(n), S(n) = O(1)
     }
 }