The population of a small country is organized into five clans - N, O, P, S, and T.
Each year exactly three of the five clans participate in the annual harvest ceremonies.
The rules specifying the order of participation of the clans in the ceremonies are as follows:
Each clan must participate at least once in any two consecutive years.
No clan participates for three consecutive years.
Participation takes place in cycles, with each cycle ending when each of the five clans has participate three times. Only then does a new cycle begin.
No cycle participates more than three times within any cycle.
대략 감은 잡겠는데, 정확히 풀지를 못하겠네요.
간략한 풀이 방법이나 팁 좀 부탁드립니다.