For example solution number 4974296 time is 0.75. This solution does not use either Z-function or KMP, just std::string::find.

Admins, is it intended solution complexity for this problem or time limit should be decreased to for example 0.5 s?

I have tried to solve this problem, using std::find and string, but failed with TL#5.
Can you please explain your idea to me?

My e-mail is: marqueewinq@gmail.com