% random list exercises

% deps


% code

rnprint(0).
rnprint(N) :-
  random(0,10,X),
  write(X),nl,
  M is N-1,
  rnprint(M).
% Yes


rnlist(0,[]).
rnlist(N,X) :-
  M is N-1,
  rnlist(M,A),
  random(0,10,B),
  append(A,[B],X).
% Yes


count(_,[],0).
count(N,[H|T],X) :-
  N = H,
  count(N,T,Out),
  X is Out + 1.
count(N,[H|T],X) :-
  not(N = H),
  count(N,T,X).
% Yes


counthelper(_,10,_,0).
counthelper(Freq,Num,List,Out) :-
  Inc is Num + 1,
  Inc < 11,
  counthelper(Freq,Inc,List,C),
  count(Num,List,M),
  M = Freq,
  Out is C + 1.
counthelper(Freq,Num,List,Out) :-
  Inc is Num + 1,
  Inc < 11,
  counthelper(Freq,Inc,List,Out).
% Yes


singleton_count(List,X) :-
  counthelper(1,0,List,X).
% Yes


doubleton_count(List,X) :-
  counthelper(2,0,List,X).
% Yes
  

rnexclusion(List,X) :-
  random(0,10,C),
  not(member(C,List)),
  X = C.
rnexclusion(List,X) :-
  rnexclusion(List,X).

rnsequence(List) :-
  rnsh(0,List).

rnsh(N,[]) :-
  N > 9.
rnsh(N,List) :-
  N < 10,
  M is N+1,
  rnsh(M,C),
  rnexclusion(C,P),
  append([P],C,List).
% Yes


iota(0,[]).
iota(N,List) :-
  M is N-1,
  iota(M,L),
  append(L,[N],List).
% Yes


sum(0,[]).
sum(N,List) :-
  N > 9,
  random(1,10,R),
  P is N-R,
  sum(P,C),
  append([R],C,List).
sum(N,List) :-
  N < 10,
  M is N+1,
  random(1,M,R),
  P is N-R,
  sum(P,C),
  append([R],C,List).
% Yes


removeAll(_,[],[]).
removeAll(N,[N|T],Out) :-
  removeAll(N,T,Out).
removeAll(N,[H|T],Out) :-
  not(N=H),
  removeAll(N,T,C),
  append([H],C,Out).
% Yes

factors(N,[]) :-
  N < 1.
factors(N,List) :-
  N > 0,
  M is N-1,
  factorh(N,M,L),
  append(L,[N],List).

factorh(_,0,[]).
factorh(N,It,List) :-
  0 is N mod It,
  Next is It-1,
  factorh(N,Next,C),
  append(C,[It],List).
factorh(N,It,List) :-
  not(0 is N mod It),
  Next is It-1,
  factorh(N,Next,List).



% wow whats this stuff

addNumber(In,Out) :-
  random(0,10,R),
  append(In,[R],Out).

experiment --> addNumber, addNumber, addNumber.

experiment2 --> experiment, experiment, experiment, singleton_count.


  

help :-
  write('List Processing Exercise'),nl,
  write('Available predicates:'),nl,
  write('  rnprint(N) - writes N random numbers'),nl,
  write('  rnlist(N,List) - creates a List with N random numbers'),nl,
  write('  count(N,List,F) - returns F, the number of appearances of N in List'),nl,
  write('  singleton_count(List,F) - returns F, the number of single-appearing numbers in List'),nl,
  write('  doubleton_count(List,F) - returns F, the number of twice-appearing numbers in List'),nl,
  write('  rnexclusion(List,N) - returns N, a random number from 0 to 9 inclusive that is not a member of List'),nl,
  write('  rnsequence(List) - returns List, a list of 10 numbers from 0 to 9 inclusive in random order'),nl,
  write('  iota(N,List) - returns List, a list counting from 1 to N, or an empty list if N=0'),nl,
  write('  sum(N,List) - returns List, a list of elements with a sum equal to N'),nl,
  write('  removeAll(N,List,Out) - returns Out, the List with all elements N removed'),nl,
  write('  factors(N,List) - returns List, a list of all the factors of N'),nl.


% init
:-
  help.