I got the same situation and finally I found the reason:
You should consider text="" and text="And a Egg"('A' 'E' 'I' 'O' 'U' are included).
examples all use text="this a test!" made a trap！

Your pow function might run enlessly or return incorrect results because your y parameter is a double.

Hi, i'm passing the tests but i'm getting
SIGSEGV
Process exited prematurally with a SIGSEGV signal.
Which is strange because in VS 2017 everything is ok with
lots of tests and big positive and negative numbers .

Thanks very much!

Hi IcodeU,

your solution doesn't work for the large shifts. That's the problem.

For the above tests the shifts 127 and -127 are used. Your solution crasches with such shifts.

You should rework your code.

Hi IcodeU,

post your code here please and mark it as spoiler.

Hello, i get these errors:
_2_Test
✘ Expected: equal to eBIIL TLOIA!
Actual: !
_3_Test
✘ Expected: equal to Hello world!
Actual: m !

However, in VS 2017 it works fine with the inputs: "Hello World!",23 and "eBIIL TLOIA!", -23.
Any idea on what could be the problem?

Happens to me too, though my solution is correct it times out at 120000ms