nums is a strictly increasing list of positive integers. Return the k-th positive integer that is
not in nums.
Examples
Input: nums = [2, 3, 4, 7, 11], k = 5
Output: 9
Explanation: the missing positives are 1, 5, 6, 8, 9, 10, 12, ...
Input: nums = [1, 2, 3, 4], k = 2
Output: 6
Input: nums = [5], k = 3
Output: 3
Constraints
0 <= len(nums) <= 10**6,1 <= k <= 10**91 <= nums[i] <= 10**9- Required time:
O(log n); walking through the missing numbers is too slow.
Goals
- Derive a monotone quantity (missing count before index i) from the array
- Handle the answer lying beyond the last element