queue_slow.erl

-module(queue_slow).
-export([main/0]).
 
main() ->
        loop().
 
large_queue(0) -> queue:new();
large_queue(N) -> queue:in(N, large_queue(N-1)).
 
pop(Q) -> {A, B} = queue:out(Q), B.
 
pop_r(Q) -> {A, B} = queue:out_r(Q), B.
 
 
funny_pop({[],[]}) -> true;
funny_pop(Q) -> funny_pop(pop_r(pop(Q))).
 
loop() ->
        case io:fread( "","~d" ) of
                eof ->
                        true;
                {ok, X} ->
                        [Y] = X,
                        Q = large_queue(Y),
                        funny_pop(Q),
                        true
        end.