i am getting wrong answer continuously in cf on test 45 14463103 on 602A - TWO BASES - Two Bases but getting right answer for those specific inputs in my IDE!!! what's the wrong in my code!! thanks in advance

I have got time limit exceeded in many code. But i do not know how judges calculate the execution time of a code. Can anyone tell me how codeforce calculate the execution time of a code!!!

I registered in the testing round #12...but I am not seeing any problem in the contest site!!!! Where are the problems??