Question -> https://www.codechef.com/FEB16/problems/STROPR/ I have used modular/binary exponention and modular inverse(using Euler Theorem). Few of the test cases(including the sample test cases) are giving right answer. Please help me find the bug in the code. Here is the link for my code to the solution -> http://ideone.com/q8MaoZ My Submission link on Codechef -> https://www.codechef.com/viewsolution/9424744 Thanks in advance. :)