This is a variation of the classical river crossing puzzle. In these kinds of puzzles, the limitations to the solution is defined by the constraints placed on the different objects involved.
This puzzle consist of 8 persons:
1 criminal
1 policeman
1 father
1 mother
2 boys
2 girls
In this puzzle, there are a few restrictions:
the criminal cannot be with other actors without the police present
the father cannot be with the girls without the mother
the mother cannot be with the boys without the father
only the father, mother and police can operate the boat
An example of running the program:
