Given an array of integers where every integer occurs three times except for one integer, which only occurs once, find and return the non-duplicated integer. Do this in O(N) time and O(1) space.
Examples:
>>> coding_problem_40([6, 1, 3, 3, 3, 6, 6])
1
>>> coding_problem_40([13, 19, 13, 13])
19