Unfortunately there's no such shortcut. There's a standing feature request on Meta.Stackexchange.com to have link to questions get converted to their title in comments, just like they do elsewhere. See Replace links with the current question title in comments. You can upvote that feature reuqest if you want. However, that feature request has been denied for performance reasons (seems unconvincing to me, but I don't get to make such decisions).
The shortest is to just write
http://cs.stackexchange.com/q/74 in your comment. Unfortunately, the title doesn't get automatically inserted, so the link looks a bit ugly. There's no workaround that I know of: if you want to have the nice title, you have to insert it yourself, as you showed in your question. If you do that as an explicit link, you can omit the protocol and host name part of the URL (assuming you're referencing a question on the same site):
[Is Smoothed Analysis used outside academia?](/q/74).
You can use
/a/POST_NUMBER to link to an answer. Click the
share button below an answer to see its post number; the link is of the form
http://SITE/a/POST_NUMBER/USER_NUMBER, but the second number is only used to track users who share links.