Better if complexities other than O(1) may also be detected

[omkar-as]

progeval service currently accepts a solution only if has an around constant running time i.e. O(1). Would be better if it can detect complexities like O(n), O(logn), O(nlogn), etc. and accept/reject solutions based on it. This enhanced functionality will call for adding a wider spectrum of computer programming problems, mainly those which cannot be solved in O(1) time.