Missing number(s) Interview Question Redux

Question

The common interview problem of determining the missing value in a range from 1 to N has been done a thousand times over. Variations include 2 missing values up to K missing val

Answer 1

I already answered it HERE

You can also create an array of boolean of the size last_element_in_the_existing_array + 1.

In a for loop mark all the element true that are present in the existing array.

In another for loop print the index of the elements which contains false AKA The missing ones.

Time Complexity: O(last_element_in_the_existing_array)

Space Complexity: O(array.length)