Здесь вы можете использовать унификацию вместо is/2
(которая обычно используется для оценки выражений).
Например, мы можем определить ход из первой башни во вторую башню, если вторая башня пуста:
changeState((s([A|T1],[], T3)), s(T1, [A], T3)).
или мы можем переместить элемент во вторую непустую башню, учитывая, что на вершине стека находится элемент, который больше:
changeState(s([A|T1], [B|T2], T3), s(T1, [A,B|T2], T3)) :-
A < B.
Вышеприведенное приведет к 12 правилам: 3 источника, умножить на 2 пункта назначения, умножить на 2 возможности (пустой пункт назначения или непустой пункт назначения). Это не очень элегантно. Мы можем создать вспомогательный предикат, который проверяет, является ли целевой стек действительным, с помощью:
valid_stack([], _).
valid_stack([H|_], X) :-
X < H.
поэтому мы можем сжать два приведенных выше правила в:
changeState((s([A|T1], T2, T3)), s(T1, [A|T2], T3)) :-
valid_stack(T2, A).
Таким образом, получится шесть правил: три источника и два адресата.
Таким образом, нам больше не нужно проверять ходы, так как если changeState
успешно, то предлагаемый ход возможен, при условии, что исходное состояние было действительным.
Однако это не полное решение (остальное я оставлю в качестве упражнения). Вам понадобится механизм, который перечисляет возможные ходы и следит за тем, чтобы вы не попали в петлю (например, постоянно перемещая диск между двумя башнями).
После использования предиката traverse/3
получаем список ходов к цели:
?- traverse(s([1,2,3,4,5,6], [], []), S, [s([1,2,3,4,5,6], [], [])]).
S = [s([1, 2, 3, 4, 5, 6], [], []), s([2, 3, 4, 5, 6], [1], []), s([3, 4, 5, 6], [1], [2]), s([1, 3, 4, 5|...], [], [2]), s([3, 4, 5|...], [], [1, 2]), s([4, 5|...], [3], [1, 2]), s([1|...], [3], [2]), s([...|...], [...|...], [...]), s(..., ..., ...)|...] [write]
S = [s([1, 2, 3, 4, 5, 6], [], []), s([2, 3, 4, 5, 6], [1], []), s([3, 4, 5, 6], [1], [2]), s([1, 3, 4, 5, 6], [], [2]), s([3, 4, 5, 6], [], [1, 2]), s([4, 5, 6], [3], [1, 2]), s([1, 4, 5, 6], [3], [2]), s([4, 5, 6], [1, 3], [2]), s([2, 4, 5, 6], [1, 3], []), s([1, 2, 4, 5, 6], [3], []), s([2, 4, 5, 6], [3], [1]), s([4, 5, 6], [2, 3], [1]), s([1, 4, 5, 6], [2, 3], []), s([4, 5, 6], [1, 2, 3], []), s([5, 6], [1, 2, 3], [4]), s([1, 5, 6], [2, 3], [4]), s([5, 6], [2, 3], [1, 4]), s([2, 5, 6], [3], [1, 4]), s([1, 2, 5, 6], [3], [4]), s([2, 5, 6], [1, 3], [4]), s([5, 6], [1, 3], [2, 4]), s([1, 5, 6], [3], [2, 4]), s([5, 6], [3], [1, 2, 4]), s([3, 5, 6], [], [1, 2, 4]), s([1, 3, 5, 6], [], [2, 4]), s([3, 5, 6], [1], [2, 4]), s([2, 3, 5, 6], [1], [4]), s([1, 2, 3, 5, 6], [], [4]), s([2, 3, 5, 6], [], [1, 4]), s([3, 5, 6], [2], [1, 4]), s([1, 3, 5, 6], [2], [4]), s([3, 5, 6], [1, 2], [4]), s([5, 6], [1, 2], [3, 4]), s([1, 5, 6], [2], [3, 4]), s([5, 6], [2], [1, 3, 4]), s([2, 5, 6], [], [1, 3, 4]), s([1, 2, 5, 6], [], [3, 4]), s([2, 5, 6], [1], [3, 4]), s([5, 6], [1], [2, 3, 4]), s([1, 5, 6], [], [2, 3, 4]), s([5, 6], [], [1, 2, 3, 4]), s([6], [5], [1, 2, 3, 4]), s([1, 6], [5], [2, 3, 4]), s([6], [1, 5], [2, 3, 4]), s([2, 6], [1, 5], [3, 4]), s([1, 2, 6], [5], [3, 4]), s([2, 6], [5], [1, 3, 4]), s([6], [2, 5], [1, 3, 4]), s([1, 6], [2, 5], [3, 4]), s([6], [1, 2, 5], [3, 4]), s([3, 6], [1, 2, 5], [4]), s([1, 3, 6], [2, 5], [4]), s([3, 6], [2, 5], [1, 4]), s([2, 3, 6], [5], [1, 4]), s([1, 2, 3, 6], [5], [4]), s([2, 3, 6], [1, 5], [4]), s([3, 6], [1, 5], [2, 4]), s([1, 3, 6], [5], [2, 4]), s([3, 6], [5], [1, 2, 4]), s([6], [3, 5], [1, 2, 4]), s([1, 6], [3, 5], [2, 4]), s([6], [1, 3, 5], [2, 4]), s([2, 6], [1, 3, 5], [4]), s([1, 2, 6], [3, 5], [4]), s([2, 6], [3, 5], [1, 4]), s([6], [2, 3, 5], [1, 4]), s([1, 6], [2, 3, 5], [4]), s([6], [1, 2, 3, 5], [4]), s([4, 6], [1, 2, 3, 5], []), s([1, 4, 6], [2, 3, 5], []), s([4, 6], [2, 3, 5], [1]), s([2, 4, 6], [3, 5], [1]), s([1, 2, 4, 6], [3, 5], []), s([2, 4, 6], [1, 3, 5], []), s([4, 6], [1, 3, 5], [2]), s([1, 4, 6], [3, 5], [2]), s([4, 6], [3, 5], [1, 2]), s([3, 4, 6], [5], [1, 2]), s([1, 3, 4, 6], [5], [2]), s([3, 4, 6], [1, 5], [2]), s([2, 3, 4, 6], [1, 5], []), s([1, 2, 3, 4, 6], [5], []), s([2, 3, 4, 6], [5], [1]), s([3, 4, 6], [2, 5], [1]), s([1, 3, 4, 6], [2, 5], []), s([3, 4, 6], [1, 2, 5], []), s([4, 6], [1, 2, 5], [3]), s([1, 4, 6], [2, 5], [3]), s([4, 6], [2, 5], [1, 3]), s([2, 4, 6], [5], [1, 3]), s([1, 2, 4, 6], [5], [3]), s([2, 4, 6], [1, 5], [3]), s([4, 6], [1, 5], [2, 3]), s([1, 4, 6], [5], [2, 3]), s([4, 6], [5], [1, 2, 3]), s([6], [4, 5], [1, 2, 3]), s([1, 6], [4, 5], [2, 3]), s([6], [1, 4, 5], [2, 3]), s([2, 6], [1, 4, 5], [3]), s([1, 2, 6], [4, 5], [3]), s([2, 6], [4, 5], [1, 3]), s([6], [2, 4, 5], [1, 3]), s([1, 6], [2, 4, 5], [3]), s([6], [1, 2, 4, 5], [3]), s([3, 6], [1, 2, 4, 5], []), s([1, 3, 6], [2, 4, 5], []), s([3, 6], [2, 4, 5], [1]), s([2, 3, 6], [4, 5], [1]), s([1, 2, 3, 6], [4, 5], []), s([2, 3, 6], [1, 4, 5], []), s([3, 6], [1, 4, 5], [2]), s([1, 3, 6], [4, 5], [2]), s([3, 6], [4, 5], [1, 2]), s([6], [3, 4, 5], [1, 2]), s([1, 6], [3, 4, 5], [2]), s([6], [1, 3, 4, 5], [2]), s([2, 6], [1, 3, 4, 5], []), s([1, 2, 6], [3, 4, 5], []), s([2, 6], [3, 4, 5], [1]), s([6], [2, 3, 4, 5], [1]), s([1, 6], [2, 3, 4, 5], []), s([6], [1, 2, 3, 4, 5], []), s([], [1, 2, 3, 4, 5], [6]), s([1], [2, 3, 4, 5], [6]), s([], [2, 3, 4, 5], [1, 6]), s([2], [3, 4, 5], [1, 6]), s([1, 2], [3, 4, 5], [6]), s([2], [1, 3, 4, 5], [6]), s([], [1, 3, 4, 5], [2, 6]), s([1], [3, 4, 5], [2, 6]), s([], [3, 4, 5], [1, 2, 6]), s([3], [4, 5], [1, 2, 6]), s([1, 3], [4, 5], [2, 6]), s([3], [1, 4, 5], [2, 6]), s([2, 3], [1, 4, 5], [6]), s([1, 2, 3], [4, 5], [6]), s([2, 3], [4, 5], [1, 6]), s([3], [2, 4, 5], [1, 6]), s([1, 3], [2, 4, 5], [6]), s([3], [1, 2, 4, 5], [6]), s([], [1, 2, 4, 5], [3, 6]), s([1], [2, 4, 5], [3, 6]), s([], [2, 4, 5], [1, 3, 6]), s([2], [4, 5], [1, 3, 6]), s([1, 2], [4, 5], [3, 6]), s([2], [1, 4, 5], [3, 6]), s([], [1, 4, 5], [2, 3, 6]), s([1], [4, 5], [2, 3, 6]), s([], [4, 5], [1, 2, 3, 6]), s([4], [5], [1, 2, 3, 6]), s([1, 4], [5], [2, 3, 6]), s([4], [1, 5], [2, 3, 6]), s([2, 4], [1, 5], [3, 6]), s([1, 2, 4], [5], [3, 6]), s([2, 4], [5], [1, 3, 6]), s([4], [2, 5], [1, 3, 6]), s([1, 4], [2, 5], [3, 6]), s([4], [1, 2, 5], [3, 6]), s([3, 4], [1, 2, 5], [6]), s([1, 3, 4], [2, 5], [6]), s([3, 4], [2, 5], [1, 6]), s([2, 3, 4], [5], [1, 6]), s([1, 2, 3, 4], [5], [6]), s([2, 3, 4], [1, 5], [6]), s([3, 4], [1, 5], [2, 6]), s([1, 3, 4], [5], [2, 6]), s([3, 4], [5], [1, 2, 6]), s([4], [3, 5], [1, 2, 6]), s([1, 4], [3, 5], [2, 6]), s([4], [1, 3, 5], [2, 6]), s([2, 4], [1, 3, 5], [6]), s([1, 2, 4], [3, 5], [6]), s([2, 4], [3, 5], [1, 6]), s([4], [2, 3, 5], [1, 6]), s([1, 4], [2, 3, 5], [6]), s([4], [1, 2, 3, 5], [6]), s([], [1, 2, 3, 5], [4, 6]), s([1], [2, 3, 5], [4, 6]), s([], [2, 3, 5], [1, 4, 6]), s([2], [3, 5], [1, 4, 6]), s([1, 2], [3, 5], [4, 6]), s([2], [1, 3, 5], [4, 6]), s([], [1, 3, 5], [2, 4, 6]), s([1], [3, 5], [2, 4, 6]), s([], [3, 5], [1, 2, 4, 6]), s([3], [5], [1, 2, 4, 6]), s([1, 3], [5], [2, 4, 6]), s([3], [1, 5], [2, 4, 6]), s([2, 3], [1, 5], [4, 6]), s([1, 2, 3], [5], [4, 6]), s([2, 3], [5], [1, 4, 6]), s([3], [2, 5], [1, 4, 6]), s([1, 3], [2, 5], [4, 6]), s([3], [1, 2, 5], [4, 6]), s([], [1, 2, 5], [3, 4, 6]), s([1], [2, 5], [3, 4, 6]), s([], [2, 5], [1, 3, 4, 6]), s([2], [5], [1, 3, 4, 6]), s([1, 2], [5], [3, 4, 6]), s([2], [1, 5], [3, 4, 6]), s([], [1, 5], [2, 3, 4, 6]), s([1], [5], [2, 3, 4, 6]), s([], [5], [1, 2, 3, 4, 6]), s([5], [], [1, 2, 3, 4, 6]), s([1, 5], [], [2, 3, 4, 6]), s([5], [1], [2, 3, 4, 6]), s([2, 5], [1], [3, 4, 6]), s([1, 2, 5], [], [3, 4, 6]), s([2, 5], [], [1, 3, 4, 6]), s([5], [2], [1, 3, 4, 6]), s([1, 5], [2], [3, 4, 6]), s([5], [1, 2], [3, 4, 6]), s([3, 5], [1, 2], [4, 6]), s([1, 3, 5], [2], [4, 6]), s([3, 5], [2], [1, 4, 6]), s([2, 3, 5], [], [1, 4, 6]), s([1, 2, 3, 5], [], [4, 6]), s([2, 3, 5], [1], [4, 6]), s([3, 5], [1], [2, 4, 6]), s([1, 3, 5], [], [2, 4, 6]), s([3, 5], [], [1, 2, 4, 6]), s([5], [3], [1, 2, 4, 6]), s([1, 5], [3], [2, 4, 6]), s([5], [1, 3], [2, 4, 6]), s([2, 5], [1, 3], [4, 6]), s([1, 2, 5], [3], [4, 6]), s([2, 5], [3], [1, 4, 6]), s([5], [2, 3], [1, 4, 6]), s([1, 5], [2, 3], [4, 6]), s([5], [1, 2, 3], [4, 6]), s([4, 5], [1, 2, 3], [6]), s([1, 4, 5], [2, 3], [6]), s([4, 5], [2, 3], [1, 6]), s([2, 4, 5], [3], [1, 6]), s([1, 2, 4, 5], [3], [6]), s([2, 4, 5], [1, 3], [6]), s([4, 5], [1, 3], [2, 6]), s([1, 4, 5], [3], [2, 6]), s([4, 5], [3], [1, 2, 6]), s([3, 4, 5], [], [1, 2, 6]), s([1, 3, 4, 5], [], [2, 6]), s([3, 4, 5], [1], [2, 6]), s([2, 3, 4, 5], [1], [6]), s([1, 2, 3, 4, 5], [], [6]), s([2, 3, 4, 5], [], [1, 6]), s([3, 4, 5], [2], [1, 6]), s([1, 3, 4, 5], [2], [6]), s([3, 4, 5], [1, 2], [6]), s([4, 5], [1, 2], [3, 6]), s([1, 4, 5], [2], [3, 6]), s([4, 5], [2], [1, 3, 6]), s([2, 4, 5], [], [1, 3, 6]), s([1, 2, 4, 5], [], [3, 6]), s([2, 4, 5], [1], [3, 6]), s([4, 5], [1], [2, 3, 6]), s([1, 4, 5], [], [2, 3, 6]), s([4, 5], [], [1, 2, 3, 6]), s([5], [4], [1, 2, 3, 6]), s([1, 5], [4], [2, 3, 6]), s([5], [1, 4], [2, 3, 6]), s([2, 5], [1, 4], [3, 6]), s([1, 2, 5], [4], [3, 6]), s([2, 5], [4], [1, 3, 6]), s([5], [2, 4], [1, 3, 6]), s([1, 5], [2, 4], [3, 6]), s([5], [1, 2, 4], [3, 6]), s([3, 5], [1, 2, 4], [6]), s([1, 3, 5], [2, 4], [6]), s([3, 5], [2, 4], [1, 6]), s([2, 3, 5], [4], [1, 6]), s([1, 2, 3, 5], [4], [6]), s([2, 3, 5], [1, 4], [6]), s([3, 5], [1, 4], [2, 6]), s([1, 3, 5], [4], [2, 6]), s([3, 5], [4], [1, 2, 6]), s([5], [3, 4], [1, 2, 6]), s([1, 5], [3, 4], [2, 6]), s([5], [1, 3, 4], [2, 6]), s([2, 5], [1, 3, 4], [6]), s([1, 2, 5], [3, 4], [6]), s([2, 5], [3, 4], [1, 6]), s([5], [2, 3, 4], [1, 6]), s([1, 5], [2, 3, 4], [6]), s([5], [1, 2, 3, 4], [6]), s([], [1, 2, 3, 4], [5, 6]), s([1], [2, 3, 4], [5, 6]), s([], [2, 3, 4], [1, 5, 6]), s([2], [3, 4], [1, 5, 6]), s([1, 2], [3, 4], [5, 6]), s([2], [1, 3, 4], [5, 6]), s([], [1, 3, 4], [2, 5, 6]), s([1], [3, 4], [2, 5, 6]), s([], [3, 4], [1, 2, 5, 6]), s([3], [4], [1, 2, 5, 6]), s([1, 3], [4], [2, 5, 6]), s([3], [1, 4], [2, 5, 6]), s([2, 3], [1, 4], [5, 6]), s([1, 2, 3], [4], [5, 6]), s([2, 3], [4], [1, 5, 6]), s([3], [2, 4], [1, 5, 6]), s([1, 3], [2, 4], [5, 6]), s([3], [1, 2, 4], [5, 6]), s([], [1, 2, 4], [3, 5, 6]), s([1], [2, 4], [3, 5, 6]), s([], [2, 4], [1, 3, 5, 6]), s([2], [4], [1, 3, 5, 6]), s([1, 2], [4], [3, 5, 6]), s([2], [1, 4], [3, 5, 6]), s([], [1, 4], [2, 3, 5, 6]), s([1], [4], [2, 3, 5, 6]), s([], [4], [1, 2, 3, 5, 6]), s([4], [], [1, 2, 3, 5, 6]), s([1, 4], [], [2, 3, 5, 6]), s([4], [1], [2, 3, 5, 6]), s([2, 4], [1], [3, 5, 6]), s([1, 2, 4], [], [3, 5, 6]), s([2, 4], [], [1, 3, 5, 6]), s([4], [2], [1, 3, 5, 6]), s([1, 4], [2], [3, 5, 6]), s([4], [1, 2], [3, 5, 6]), s([3, 4], [1, 2], [5, 6]), s([1, 3, 4], [2], [5, 6]), s([3, 4], [2], [1, 5, 6]), s([2, 3, 4], [], [1, 5, 6]), s([1, 2, 3, 4], [], [5, 6]), s([2, 3, 4], [1], [5, 6]), s([3, 4], [1], [2, 5, 6]), s([1, 3, 4], [], [2, 5, 6]), s([3, 4], [], [1, 2, 5, 6]), s([4], [3], [1, 2, 5, 6]), s([1, 4], [3], [2, 5, 6]), s([4], [1, 3], [2, 5, 6]), s([2, 4], [1, 3], [5, 6]), s([1, 2, 4], [3], [5, 6]), s([2, 4], [3], [1, 5, 6]), s([4], [2, 3], [1, 5, 6]), s([1, 4], [2, 3], [5, 6]), s([4], [1, 2, 3], [5, 6]), s([], [1, 2, 3], [4, 5, 6]), s([1], [2, 3], [4, 5, 6]), s([], [2, 3], [1, 4, 5, 6]), s([2], [3], [1, 4, 5, 6]), s([1, 2], [3], [4, 5, 6]), s([2], [1, 3], [4, 5, 6]), s([], [1, 3], [2, 4, 5, 6]), s([1], [3], [2, 4, 5, 6]), s([], [3], [1, 2, 4, 5, 6]), s([3], [], [1, 2, 4, 5, 6]), s([1, 3], [], [2, 4, 5, 6]), s([3], [1], [2, 4, 5, 6]), s([2, 3], [1], [4, 5, 6]), s([1, 2, 3], [], [4, 5, 6]), s([2, 3], [], [1, 4, 5, 6]), s([3], [2], [1, 4, 5, 6]), s([1, 3], [2], [4, 5, 6]), s([3], [1, 2], [4, 5, 6]), s([], [1, 2], [3, 4, 5, 6]), s([1], [2], [3, 4, 5, 6]), s([], [2], [1, 3, 4, 5, 6]), s([2], [], [1, 3, 4, 5, 6]), s([1, 2], [], [3, 4, 5, 6]), s([2], [1], [3, 4, 5, 6]), s([], [1], [2, 3, 4, 5, 6]), s([1], [], [2, 3, 4, 5, 6]), s([], [], [1, 2, 3, 4, 5, 6])]
В SWI-Prolog нужно нажать W, чтобы попросить интерактивную оболочку распечатать полный список.
person
Willem Van Onsem
schedule
17.12.2018
;
12 раз, чтобы запросить следующее решение. Это то, что случилось? Вы хотите сказать, что после нажатия;
в 12-й раз вы ждали 10 минут, не получив следующего решения? - person Will Ness   schedule 17.12.2018;
, нажмитеw
один раз, затем нажмите.
. Скопируйте результат и разместите здесь. - person Will Ness   schedule 17.12.2018traverse(..,S,...),print(S)
для печатиS
, в этом случае он напечатает весь список в STDOUT. - person Willem Van Onsem   schedule 17.12.2018