This refers to the problem “Sereja and Shuffling” in the August Challenge 2014 currently underway .
5 people seem to have exactly solved the problem . On a careful consideration it seems an exact solution can be reached for most of the test cases .
The RAW score formula is (INIT - S) / INIT , where S has to minimized and can be at minimum zero . So the best raw score for a test file is 1 . So only taking into account scores for 4 test files ( out of 20 ) a score of 0.2 would be achieved at best which the top 5 contestants for the challenge problem have achieved .
The contest is only halfway , and it would be better if codechef admin’s add another challenge problem .
Also it is time to rethink the process by which challenge problems are accepted for inclusion in a LONG contest .