Given two arrays (the first array and the second array) of the
same size, each consisting of n positive integers, write a
program to determine how many unique integers the second
array has. Here a unique integer means that it shows only once
in the second array but does not show in the first array. For
example, if the first array is [1, 5, 3, 6, 8] and the second array is
[2, 4, 2, 5, 9] (with n=5), the second array has two unique
integers (4 and 9). What is the complexity of the program?