LC 1539 [E] Kth Missing Positive Number

class Solution:
    def findKthPositive(self, A: List[int], k: int) -> int:
        n = len(A)
        l = 0
        r = n
        while l < r:
            m = (l + r) // 2
            numMissPos = A[m] - m - 1
            if numMissPos < k:
                l = m + 1
            else:
                r = m
        return l + k