Update readme

Author: Khanh Do

README.md

@@ -5,8 +5,9 @@ complexity and how I arrive at them.
 
 For expediency, when problems involve an array, I am OK with using a Python list
 instead and using the following operations:
-- `for i in range(n)` to iterate over the list
--  `for i in range(bigger, smaller, -1)` to iterate backwards
+- `for i in range(n):` to iterate over the list
+-  `for i in range(bigger, smaller, -1):` to iterate backwards
+- `for i, v in enumerate(nums):` to iterate over index and value simultaneously
 - `nums[-1]` to get the last element
 
 While these operations are indeed Pythonic, they don't provide any extra