/// A case of catastrophic backtracking in Dart

///---------------------------------------------

/// example provided by Martin Todorov

///

/// regex: (a*)*b

/// strings: aa...a

///

/// run with

///

///    dart catastrophic.dart n

main(List<String> args) {

  final n = int.parse(args[0]);

  final evilRegex = RegExp("(a*)*b");

  for(int i = 1; i <= n; i++) {

    final toMatch = "a" * i;

    final stopwatch = Stopwatch()..start();

    evilRegex.hasMatch(toMatch);

    print("$i a's matched in ${stopwatch.elapsed}");

  }

}