ok, I know that small factorial has a solution that is now known to the entire codechef( maybe an exaggeration )…but, is it legal, well, allowed to just use one of the library feature of a language ? ( in Dlang, there is a BigInt lirary )
Yes, AFAIK, it’s legal to use any library feature.
You can also just use Python and solve it using in-built big integers which are of arbitrary precision.
umm…I kinda already used Dlang’s library big integers…