Prolog 31/01/2017

:- writeln('*******************'),
    writeln('Prolog is fun! :)'),
    writeln('31/01/2017'),
    writeln('*******************').

/* Zadatcha 1: Sve kombinacije neke liste duzine N,
 * a elementi liste slova O(0) i P(1),
 * i ne smeju 2 slova P jedno pored drugog */
zad1(N, L):- proc1(N, 'O', L).
proc1(0, _, []).
proc1(N, Last, [ 'O' | L1]):- N > 0,
    Last == 'P',
    N1 is N - 1,
    proc1(N1, 'O', L1).
proc1(N, _, [ 'O' | L1 ]):- N > 0,
    N1 is N - 1,
    proc1(N1, 'O', L1).
proc1(N, Last, [ 'P' | L1 ]):- N > 0,
    Last == 'O',
    N1 is N - 1,
    proc1(N1, 'P', L1).

zad2(_, [], G, G).
zad2([ G1 | R1 ], [ G2 | R2 ], K, N):- G1 == G2,
    zad2(R1, R2, K, N).
zad2([ G1 | R1 ], [ G2 | R2 ], K, N):- G1 == G2,
    K1 is K + 1,
    zad2(R1, [ G2 | R2], K1, N).
zad2([ G1 | R1 ], [ G2 | R2 ], K, N):- not(G1 == G2),
    K1 is K + 1,
    zad2(R1, [ G2 | R2 ], K1, N).


zadnji([ E ], E).
zadnji([ _ | R ], E):- zadnji(R, E).