(Challenge) - Class schedule

Question

input-map of classes(as in classes in uni) and list of times for which the classes are available. eg:{"Cs 1":[1030,1230]}.
Output expected- classes with times such that there is no time conflict. If there is more than 1 solution all of them should be the output. if no such combinations are possible , output:"does not exist"

Answer 1

How about no