Data commit

Task/Sexy-primes/Prolog/sexy-primes-1.pro

@@ -0,0 +1,47 @@
+sexy_prime_group(1, N, _, [N]):-
+    is_prime(N),
+    !.
+sexy_prime_group(Size, N, Limit, [N|Group]):-
+    is_prime(N),
+    N1 is N + 6,
+    N1 =< Limit,
+    S1 is Size - 1,
+    sexy_prime_group(S1, N1, Limit, Group).
+
+print_sexy_prime_groups(Size, Limit):-
+    findall(G, (is_prime(P), P =< Limit, sexy_prime_group(Size, P, Limit, G)), Groups),
+    length(Groups, Len),
+    writef('Number of groups of size %t is %t\n', [Size, Len]),
+    last_n(Groups, 5, Len, Last, Last_len),
+    writef('Last %t groups of size %t: %t\n\n', [Last_len, Size, Last]).
+
+last_n([], _, L, [], L):-!.
+last_n([_|List], Max, Length, Last, Last_len):-
+    Max < Length,
+    !,
+    Len1 is Length - 1,
+    last_n(List, Max, Len1, Last, Last_len).
+last_n([E|List], Max, Length, [E|Last], Last_len):-
+    last_n(List, Max, Length, Last, Last_len).
+
+unsexy(P):-
+    P1 is P + 6,
+    \+is_prime(P1),
+    P2 is P - 6,
+    \+is_prime(P2).
+
+main(Limit):-
+    Max is Limit + 6,
+    find_prime_numbers(Max),
+    print_sexy_prime_groups(2, Limit),
+    print_sexy_prime_groups(3, Limit),
+    print_sexy_prime_groups(4, Limit),
+    print_sexy_prime_groups(5, Limit),
+    findall(P, (is_prime(P), P =< Limit, unsexy(P)), Unsexy),
+    length(Unsexy, Count),
+    writef('Number of unsexy primes is %t\n', [Count]),
+    last_n(Unsexy, 10, Count, Last10, _),
+    writef('Last 10 unsexy primes: %t', [Last10]).
+
+main:-
+    main(1000035).

Task/Sexy-primes/Prolog/sexy-primes-2.pro

@@ -0,0 +1,42 @@
+:- module(prime_numbers, [find_prime_numbers/1, is_prime/1]).
+:- dynamic is_prime/1.
+
+find_prime_numbers(N):-
+    retractall(is_prime(_)),
+    assertz(is_prime(2)),
+    init_sieve(N, 3),
+    sieve(N, 3).
+
+init_sieve(N, P):-
+    P > N,
+    !.
+init_sieve(N, P):-
+    assertz(is_prime(P)),
+    Q is P + 2,
+    init_sieve(N, Q).
+
+sieve(N, P):-
+    P * P > N,
+    !.
+sieve(N, P):-
+    is_prime(P),
+    !,
+    S is P * P,
+    cross_out(S, N, P),
+    Q is P + 2,
+    sieve(N, Q).
+sieve(N, P):-
+    Q is P + 2,
+    sieve(N, Q).
+
+cross_out(S, N, _):-
+    S > N,
+    !.
+cross_out(S, N, P):-
+    retract(is_prime(S)),
+    !,
+    Q is S + 2 * P,
+    cross_out(Q, N, P).
+cross_out(S, N, P):-
+    Q is S + 2 * P,
+    cross_out(Q, N, P).