-----------PERMUTATION/MEMBER/CONCATENATION---------------------
% ---------------------------------------------------------------------------------------------------------
% Permuatation      input = perm([a,b,c,d],X).
perm(List,[H|Perm]):-delete(H,List,Rest),perm(Rest,Perm).
perm([],[]).

delete(X,[X|T],T).
delete(X,[H|T],[H|NT]):-delete(X,T,NT).

% ---------------------------------------------------------------------------------------------------------
% Memeber       input = list_member(b,[a,b,c]).
list_member(X,[X|_]).
list_member(X,[_|TAIL]) :- list_member(X,TAIL).

% ---------------------------------------------------------------------------------------------------------
% Concatenation         input = list_concat([1,2],[a,b,c],NewList).
list_concat([],L,L).
list_concat([X1|L1],L2,[X1|L3]) :- list_concat(L1,L2,L3).


----------------------INTERSECTION UNION----------------------------------
% ---------------------------------------------------------------------------------------------------------
% Union      input = list_union([a,b,c,d,e],[a,e,i,o,u],L3).
list_member(X,[X|_]).
list_member(X,[_|TAIL]) :- list_member(X,TAIL).

list_union([X|Y],Z,W) :- list_member(X,Z),list_union(Y,Z,W).
list_union([X|Y],Z,[X|W]) :- \+ list_member(X,Z), list_union(Y,Z,W).
list_union([],Z,Z).

% ---------------------------------------------------------------------------------------------------------
% Intersection      input = list_intersect([a,b,c,d,e],[],L3).
list_member(X,[X|_]).
list_member(X,[_|TAIL]) :- list_member(X,TAIL).

list_intersect([X|Y],Z,[X|W]) :-
   list_member(X,Z), list_intersect(Y,Z,W).
list_intersect([X|Y],Z,W) :-
   \+ list_member(X,Z), list_intersect(Y,Z,W).
list_intersect([],Z,[]).

---------------------------------MONKEY BANANA--------------------------------------------------------
% ---------------------------------------------------------------------------------------------------------
% Union      input = list_union([a,b,c,d,e],[a,e,i,o,u],L3).
list_member(X,[X|_]).
list_member(X,[_|TAIL]) :- list_member(X,TAIL).

list_union([X|Y],Z,W) :- list_member(X,Z),list_union(Y,Z,W).
list_union([X|Y],Z,[X|W]) :- \+ list_member(X,Z), list_union(Y,Z,W).
list_union([],Z,Z).

% ---------------------------------------------------------------------------------------------------------
% Intersection      input = list_intersect([a,b,c,d,e],[],L3).
list_member(X,[X|_]).
list_member(X,[_|TAIL]) :- list_member(X,TAIL).

list_intersect([X|Y],Z,[X|W]) :-
   list_member(X,Z), list_intersect(Y,Z,W).
list_intersect([X|Y],Z,W) :-
   \+ list_member(X,Z), list_intersect(Y,Z,W).
list_intersect([],Z,[]).