1060. Missing Element in Sorted Array

sa

class Solution:
    def missingElement(self, nums: List[int], k: int) -> int:

        def totalMissing(index):
            return nums[index] - nums[0] - index

        n = len(nums)

        if totalMissing(n - 1) < k:
            return nums[n - 1] + k - totalMissing(n - 1)


        l, r = 0, n - 1

        while l < r:
            m = (l + r) // 2

            if totalMissing(m) < k:
                l = m + 1
            else:
                r = m

        return nums[l - 1] + k - totalMissing(l - 1)