11551 - Experienced Endeavour

[ani_mitr86]

I think that there is a mistake in the second image. The subscript of the last number should be i, x(i-1) and not i, x(i). I hope some admin notices this and fix the mistake. I don't know where else to report this so I am posting this here.

[Robert Gerbicz]

The whole image is dirty and small, magnifying doesn't help. Guessing the problem took me more time than solving it on the contest.

[azk84]

I'm getting TLE. My aproach is simply calculating sum R times. Can somebody give some hints plz? I don't know another solution for this problem.

[lyhung]

Try to convert the problem into result = a^r; Find that in ln(r).

[azk84]

Thanks lyhung. You said to convert problem to A^r, so I tried to think different and I think I can use n*n matrix A that contains 1 & 0 (for given sum rules), and multiply A^r into original numbers, but I don't know how to compute A^r efficiently (instead of multiplying A into itself r times). Plz give me some more hint. Maybe I haven't understood your previous hint at all .
BTW, sorry for my very bad English

[azk84]

Finally accepted with time 0.100 . Special thanX to lyhung