This is by far the most difficult WSQ of all, first you need to know how to compile and run with the big integer library, and then you need to know how to use the big integer type and how to convert form string to biginteger and viceversa. You will need a lot of loops, so I hope you know how to use them.
To setup your Big Int library watch this video: https://www.youtube.com/watch?v=PHZYtOhFAZs
if you don´t even know what the program should do, watch this video: https://www.youtube.com/watch?v=KMDDoipS9H0
check my code: https://github.com/MiguelAngelCardenas/WSQ11
GOOD LUCK, YOU´LL NEED IT!!