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December 27, 2015 19:39
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Encode and de-code run-length encoding in Prolog with a single predicate.
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encode([], []). | |
encode(XS, [E|ES]) :- | |
reverse(XS, XSReversed), | |
append(XRightReversed, XLeft, XSReversed), | |
XLeft \= [], | |
expand(XLeft, E), | |
reverse(XRightReversed, XRight), | |
encode(XRight, ES). | |
expand([X|XT], [Count, X]) :- expand(XT, [SubCount, X]), succ(SubCount, Count). | |
expand([], [0, _]). |
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