% Otter solution for Linear Peg Solitaire, 4 pegs of each color
% by Robert Keller
% The move sequence is recorded and returned as the answer.
% mw = move white, mr = move red
% jw = jump white, jr = jump red

set(auto).

list(usable).

move(s(w(x), y), s(x, w(y)), mw).
move(s(x, r(y)), s(r(x), y), mr).

move(s(r(w(x)), y), s(x, r(w(y))), jw).
move(s(x, w(r(y))), s(w(r(x)), y), jr).

reachable(s(w(w(w(w(c)))), r(r(r(r(c))))), []).

-reachable(x, z) | -move(x, y, v) | reachable(y, [v | z]).

-reachable(s(r(r(r(r(c)))), w(w(w(w(c))))), z) | $ans(z).

end_of_list.