The missionaries and cannibals problem, is a classic river-crossing problem. It is a well-known toy problem in artificial intelligence that can be defined as follows-

 

“On one bank of a river are three missionaries and three cannibals. There is one boat available that can hold up to two people and that they would like to use to cross the river. If the cannibals ever outnumber the missionaries on either of the river’s banks, the missionaries will get eaten.

How can the boat be used to safely carry all the missionaries and cannibals across the river?”