3 cannibals and 3 missionaries have to move to the other side of the river. There is a single boat which can accommodate at most 2 passengers at a time. What is the minimum number of times the boat have to cross the river?
Details and Assumptions:
The boat couldn't travel empty.
When there is on one side, more cannibals than missionaries, they eat them.
When the boat is docked, all the cannibals will want to alight to eat the missionaries if possible.