Given an array of integers, find the first missing positive integer in linear time and constant space. You can modify the input array in-place.
Example:
>>> coding_problem_04([3, 4, -1, 1])
2
>>> coding_problem_04([1, 2, 0])
3
>>> coding_problem_04([4, 1, 2, 2, 2, 1, 0])
3