BIA S11

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solve(S) :- S = [_,_,_,_,_],
nationality(O1,englishman),color(O1,red),member(O1,S),
color(O2,green),drink(O2,coffee),member(O2,S),
nationality(O3,italian),drink(O3,tea),member(O3,S),
color(O4,yellow),cigarette(O4,kent),member(O4,S),
drink(O5,milk),middle(O5,S),
nationality(O6,russian),leftmost(O6,S),
cigarette(OA7,marlboro),pet(OB7,fox),near(OA7,OB7,S),
cigarette(OA8,kent),pet(OB8,horse),near(OA8,OB8,S),
drink(O9,juice),cigarette(O9,pall_mall),member(O9,S),
nationality(O10,japanese),cigarette(O10,assos),member(O10,S),
nationality(OA11,russian),color(OB11,blue),near(OA11,OB11,S),
nationality(O12,spanish),pet(O12,dog),member(O12,S),
pet(O13,snake),cigarette(O13,camel),member(O13,S),
color(OA14,gray),color(OB14,green),near(OA14,OB14,S),
pet(OA15,cat),drink(OB15,vodka),lateral(OA15,S),lateral(OB15,S).

color([Color,_,_,_,_],Color).
nationality([_,Nationality,_,_,_],Nationality).
drink([_,_,Drink,_,_],Drink).
cigarette([_,_,_,Cigarette,_],Cigarette).
pet([_,_,_,_,Pet],Pet).
leftmost(X,[X,_,_,_,_]).
middle(X,[_,_,X,_,_]).
lateral(X,[X,_,_,_,_]).
lateral(X,[_,_,_,_,X]).
left(A,B,S) :-
append(_,[A,B|_],S).
near(A,B,S) :-
left(A,B,S).
near(A,B,S) :-
left(B,A,S).

solve_cities(S) :- S = [_, _, _, _], member(a, S), member(b, S), member(c, S), member(d, S), distance(a, c, S, DAC), distance(c, d, S, DCD), distance(b, c, S, DBC), distance(b, d, S, DBD), DAC > DCD, DBC < DBD.

distance(A, B, List, D) :- nth0(IndexA, List, A), nth0(IndexB, List, B),
	abs(IndexA - IndexB, D).

solve_pr(S) :- S = [_, _], l3(S).

l1(S) :- S = [p, t].
l2(S) :- S = [p, t]; S = [t, p].
l3(S) :- l1(S), not(l2(S)).
l3(S) :- l2(S), not(l1(S)).

solve9 :-
	StartingState = [1,3,3,0,0],
	depth_first_search([],StartingState,Solution),
	write(Solution),
	nl.

depth_first_search(CurrentPath,CurrentState,Solution) :-
	CurrentState=[-1,0,0,3,3],
	Solution=[CurrentState|CurrentPath].

depth_first_search(CurrentPath,CurrentState,Solution) :-
	successor(CurrentState,NewState),
	not(member(NewState,CurrentPath)),
	depth_first_search([CurrentState|CurrentPath],NewState,Solution).

%one miss
successor([Side,LM,LC,RM,RC],[NewSide,NewLM,LC,NewRM,RC]) :-
	NewLM is LM-1*Side,
	NewRM is RM+1*Side,
	NewSide is (-1)*Side,
	test(NewLM,LC,NewRM,RC).

%two can
successor([Side,LM,LC,RM,RC],[NewSide,LM,NewLC,RM,NewRC]) :-
	NewLC is LC-2*Side,
	NewRC is RC+2*Side,
	NewSide is (-1)*Side,
	test(LM,NewLC,RM,NewRC).

%one can
successor([Side,LM,LC,RM,RC],[NewSide,LM,NewLC,RM,NewRC]) :-
	NewLC is LC-1*Side,
	NewRC is RC+1*Side,
	NewSide is (-1)*Side,
	test(LM,NewLC,RM,NewRC).

%two miss
successor([Side,LM,LC,RM,RC],[NewSide,NewLM,LC,NewRM,RC]) :-
	NewLM is LM-2*Side,
	NewRM is RM+2*Side,
	NewSide is (-1)*Side,
	test(NewLM,LC,NewRM,RC).

%one mis one can
successor([Side,LM,LC,RM,RC],[NewSide,NewLM,NewLC,NewRM,NewRC]) :-
	NewLC is LC-1*Side,
	NewRC is RC+1*Side,
	NewLM is LM-1*Side,
	NewRM is RM+1*Side,
	NewSide is (-1)*Side,
	test(LM,NewLC,RM,NewRC).

test(LeftMissionaries,LeftCannibals,RightMissionaries,RightCannibals) :-
	LeftMissionaries>=0,
	LeftCannibals>=0,
	RightMissionaries>=0,
	RightCannibals>=0,
	LeftMissionaries>=LeftCannibals,
	RightMissionaries>=RightCannibals.

test(LeftMissionaries,LeftCannibals,RightMissionaries,RightCannibals) :-
	LeftMissionaries>=0,
	LeftCannibals>=0,
	RightMissionaries>=0,
	RightCannibals>=0,
	LeftMissionaries>=LeftCannibals,
	RightMissionaries=0.

test(LeftMissionaries,LeftCannibals,RightMissionaries,RightCannibals) :-
	LeftMissionaries>=0,
	LeftCannibals>=0,
	RightMissionaries>=0,
	RightCannibals>=0,
	LeftMissionaries=0,
	RightMissionaries>=RightCannibals.

solve_h :- StartingState = [3,0,0], dp_search([], StartingState, Solution), write(Solution), nl.

dp_search(CurPath, CurState, Solution) :-
	CurState = [0, 0, 3],
	Solution = [CurState|CurPath].

dp_search(CurrentPath,CurrentState,Solution) :-
	successor_h(CurrentState,NewState),
	not(member(NewState,CurrentPath)),
	dp_search([CurrentState|CurrentPath],NewState,Solution).

successor_h([Disk1, Disk2, Disk3], [NewDisk1, NewDisk2, Disk3]) :-
	Disk1 > 0,
	NewDisk1 is Disk1-1,
	NewDisk2 is Disk2+1.

successor_h([Disk1, Disk2, Disk3], [NewDisk1, Disk2, NewDisk3]) :-
	Disk1 > 0,
	NewDisk1 is Disk1-1,
	NewDisk3 is Disk3+1.

successor_h([Disk1, Disk2, Disk3], [NewDisk1, NewDisk2, Disk3]) :-
	Disk2 > 0,
	NewDisk2 is Disk2-1,
	NewDisk1 is Disk1+1.

successor_h([Disk1, Disk2, Disk3], [Disk1, NewDisk2, NewDisk3]) :-
	Disk2 > 0,
	NewDisk2 is Disk2-1,
	NewDisk3 is Disk3+1.

successor_h([Disk1, Disk2, Disk3], [NewDisk1, Disk2, NewDisk3]) :-
	Disk3 > 0,
	NewDisk3 is Disk3-1,
	NewDisk1 is Disk1+1.

successor_h([Disk1, Disk2, Disk3], [Disk1, NewDisk2, NewDisk3]) :-
	Disk3 > 0,
	NewDisk3 is Disk3-1,
	NewDisk2 is Disk2+1.