18 lines
498 B
Plaintext
18 lines
498 B
Plaintext
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partition([], _, [], []).
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partition([X|Xs], Pivot, Smalls, Bigs) :-
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( X @< Pivot ->
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Smalls = [X|Rest],
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partition(Xs, Pivot, Rest, Bigs)
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; Bigs = [X|Rest],
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partition(Xs, Pivot, Smalls, Rest)
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).
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quicksort([]) --> [].
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quicksort([X|Xs]) -->
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{ partition(Xs, X, Smaller, Bigger) },
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quicksort(Smaller), [X], quicksort(Bigger).
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perfect(N) :-
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between(1, inf, N), U is N // 2,
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findall(D, (between(1,U,D), N mod D =:= 0), Ds),
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sumlist(Ds, N).
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