Please,give me some hints or advices to solve this problem

help fr5om mathemation.
For me was interesting mathematical nature of the problem.
I got Ac under next understanding.
We must find volume of intersection [l.r]
with dison union of [kx,ky] and [k0*x,infinity]

Thank you for your answer. I'm sorry, but i did not understand your method. Can you describe your method more widely.

Form disjoint segments:[kx,ky],k=1,2,3..
When [kx,ky] will intersect with [(k+1)x-1,(k+1)y]
at k=k0:stop. From this moment we have [k0*x,infinity[
After standard programming task: find intersection
of given segment[l,r] and disjoint system of closed segments.

Edited by author 14.10.2009 17:30

Edited by author 15.10.2009 19:22

Congratulage!
To implment that isue to be great!

Very interesting problem, took me 2 days :).   I started out wrong, but then saw the progression of [kx,ky] and the gaps between them.   My solution subtracts the gaps from [l,r].   I had an initial misconception of the progression of the gaps, but corrected it and got AC.  It's interesting that if y > x then the gaps will always shrink to size zero, eventually.