HackerCards is a trendy new card game. Each type of HackerCard has a distinct ID number greater that or equals to 1, and the cost of each HackerCard equals its ID number. For example, HackerCard 1 costs 1, HackerCard 5 costs 5, and so on.
This is a companion discussion topic for the original entry at https://algo.monster/problems/citadel-oa-birthday-card-collection/