RosettaCodeData/Task/Balanced-brackets/Erlang/balanced-brackets.erl

30 lines
820 B
Erlang

-module( balanced_brackets ).
-export( [generate/1, is_balanced/1, task/0] ).
generate( N ) ->
[generate_bracket(random:uniform()) || _X <- lists:seq(1, 2*N)].
is_balanced( String ) -> is_balanced_loop( String, 0 ).
task() ->
lists:foreach( fun (N) ->
String = generate( N ),
Result = is_balanced( String ),
io:fwrite( "~s is ~s~n", [String, task_balanced(Result)] )
end,
lists:seq(0, 5) ).
is_balanced_loop( _String, N ) when N < 0 -> false;
is_balanced_loop( [], 0 ) -> true;
is_balanced_loop( [], _N ) -> false;
is_balanced_loop( [$[ | T], N ) -> is_balanced_loop( T, N + 1 );
is_balanced_loop( [$] | T], N ) -> is_balanced_loop( T, N - 1 ).
generate_bracket( N ) when N =< 0.5 -> $[;
generate_bracket( N ) when N > 0.5 -> $].
task_balanced( true ) -> "OK";
task_balanced( false ) -> "NOT OK".