The starting state of the problem.

It is this object that will be modified by apply_action and backtrack.

Property definitions

	# The starting state of the problem.
	# It is this object that will be modified by `apply_action` and `backtrack`.
	fun initial_state: S is abstract

lib/ai/backtrack.nit:44,2--46,33

	# The initial state has no queens; so, no occupied rows.
	redef fun initial_state do return new Array[Int]

lib/ai/examples/queens.nit:50,2--51,49