Search from the end in a sorted array (variant)

Problem Given a non-decreasing sorted integer array nums (length n) and a target value target. Find target starting from the end of the array and return the last index where target appears in nums. If target does not exist, return -1. Note: “search from the end” means the result should be the last occurrence. You may implement it linearly or with binary search, but be ready to explain the complexity. Follow-up If there are many duplicates, how do you ensure you still return the last position? Can you achieve O(log n)? I/O Input: integer array nums, integer target Output: integer, the last index of target (or -1 if not found) Constraints 0 <= n <= 2 * 10^5 -10^9 <= nums[i], target <= 10^9 nums is sorted in non-decreasing order Examples nums = [1,2,2,2,3], target = 2 -> 3 nums = [1,1,1], target = 1 -> 2 nums = [1,2,3,4], target = 5 -> -1 nums = [], target = 1 -> -1 nums = [2,2,2,2], target = 2 -> 3 Example Input [1,2,2,2,3] 2 Output 3