string [] inputs = {" sdfasf asdf ", " wwwwww wwwwwww ", " aaaaa bbbb ccccccc"};
foreach (string input in inputs)
{
var match = Regex.Match (input, @"^\s*(\w)(?:\1|\s)*$");
Console.WriteLine (input + "\t" + match.Success);
}
, , javascript. # :
sdfasf asdf False
wwwwww wwwwwww True
aaaaa bbbb ccccccc False