I am sure that all 0.015- 0.031 submissions aren't honest.
My program really solve the task in [1-40] ~ 0.015
[1-50] - 2-3 s. .After I simply placed an answer
at the beginning of the program.

My program doesn't use precalc at all. Time is about 0.5 sec.

Jury solution without precalc works about 0.15 sec

I just submitted a calculating code, which got accepted and ran only within 0.14 sec. I did not use extensive knowledge of math but just counted all the number of combination and stored it in double, which was enough in this case.

Edited by author 24.12.2010 02:06

Now, after optimized a little bit, my code ran within 0.078 sec.

Edited by author 24.12.2010 02:11