tut3.pl

% recodex: revize

person(O) :- member(O, [david, thomas, emma, stella]).

across(david, thomas).
across(thomas, david).
across(emma, stella).
across(stella, emma).

distinct(A, B, C, D) :-
    person(A), person(B), person(C), person(D),
    A \= B, A \= C, A \= D, B \= C, B \= D, C \= D.

solve(Dumplings, Pasta, Soup, Trout) :-
    distinct(Dumplings, Pasta, Soup, Trout),
    distinct(Beer, Cider, IcedTea, Wine),
    across(Cider, Trout),
    Dumplings = Beer,
    Soup = Cider,
    across(Pasta, Beer),
    IcedTea \= david,
    Wine = emma,
    Dumplings \= stella.

% addBit(A, B, CarryIn, R, CarryOut)
addBit(zero, zero, zero, zero, zero).
addBit(one, zero, zero, one, zero).
addBit(zero, one, zero, one, zero).
addBit(zero, zero, one, one, zero).
addBit(one, one, zero, zero, one).
addBit(one, zero, one, zero, one).
addBit(zero, one, one, zero, one).
addBit(one, one, one, one, one).

add(X3, X2, X1, X0, Y3, Y2, Y1, Y0, Z4, Z3, Z2, Z1, Z0) :-
    addBit(X0, Y0, zero, Z0, C0),
    addBit(X1, Y1, C0, Z1, C1),
    addBit(X2, Y2, C1, Z2, C2),
    addBit(X3, Y3, C2, Z3, Z4).

% generovani seznamu dane delky
gen_length([], 0).
gen_length([_|R], N) :-
    N > 0, PN is N - 1, gen_length(R, PN).

% proc nefunguje jako gen_length([1,2,3], R)?

:- use_module(library(clpfd)).

gen_length2([], 0).
gen_length2([_|R], N) :-
    N #> 0, PN #= N - 1, gen_length2(R, PN).

opposite(left, right).
opposite(right, left).

% minheap - nil, node(Dir, X, L, R)
heap_insert(V, nil, node(left, V, nil, nil)).
heap_insert(V, node(Dir, X, L, R), node(NewDir, NewX, NewL, NewR)) :-
    opposite(Dir, NewDir),
    (V < X, NewX = V, ToInsert = X; V >= X, NewX = X, ToInsert = V),
    (Dir = left, heap_insert(ToInsert, L, NewL), NewR = R; Dir = right, heap_insert(ToInsert, R, NewR), NewL = L).

% korenove stromy
% node(Val, [SubTree1, SubTree2, ..., SubTreeN])

add_one(_, V, V2) :- V2 is V + 1.

length_foldl(List, L) :- foldl(add_one, List, 0, L).