经典的MC问题(野人和传教士问题)，给定人数和船载人的数目，即可给出一个解，解的形式是一个三元组的序列，分别表示每一步之后左岸的人数和船的位置。-Classic MC problem (Savage and missionaries problem), given the number and the number of ships manned, to give a solution, the solution in the form of a sequence of triples, res