I believe the variable r can be quiet large and will take over 6000ms to complete when r is large for multiple tests. So in other words, your solution isn't efficient enough to complete this kata in the required time boundaries. You may want to rethink your stratergy.

you have an infinite loop somewhere. You need to recheck your code and make sure there are no loops, this isnt an issue with the kata and should therefore resolve the issue. :)