Write code that enhances all arrays such that you can call the upperBound() method on any array and it will return the last index of a given target number. nums is a sorted ascending array of numbers that may contain duplicates. If the target number is not found in the array, return -1.

 

Example 1:

Input: nums = [3,4,5], target = 5
Output: 2
Explanation: Last index of target value is 2

Example 2:

Input: nums = [1,4,5], target = 2
Output: -1
Explanation: Because there is no digit 2 in the array, return -1.

Example 3:

Input: nums = [3,4,6,6,6,6,7], target = 6
Output: 5
Explanation: Last index of target value is 5

 

Constraints:

• 1 <= nums.length <= 104
• -104 <= nums[i], target <= 104
• nums is sorted in ascending order.

 

Follow up: Can you write an algorithm with O(log n) runtime complexity?