as the title
thanks in advance!

Diagram of Voronoy, of course.

Well well, the second problem on Timus that should be solved with diagram of Voronoy

Well well, the second problem on Timus that should be solved with diagram of Voronoy

What one was first?

1504

Where can I read about diagram of Voronoy?

Preparata, Shajmos. Computational geometry. An introdution.

This problem can be easily solved WITHOUT Voronoi's diagram.
I didn't write 1504 yet, but it also doesn't require such complicated methods.

I got AC used diagram of voronoi.
Kit, please send me your program - efrcom@inbox.ru

It's very interesting for me, how solved it without voronoi's diagram.

I was not talking about 1504. I was talking about 1369 - the Cockroaches problem. Originally it was possible to solve the task with quadtree. But after new tests added to the task quadtree does not work. Therefore a more sophisticated structure is required.

It's not clear. The plants are guaranteed to have integer coordinates. Is that true for Saddam too? If so, it's might be a simple binary search

No, it is said that Sassam is somewhere in the circle - not required to be at an integer coordinate. (in fact he is somewhere else but... that's the problem statement - not up to date).
-- it would be good to post such question in other topics for the future

He might be anywhere within the circle.

P.S. It is a pity Saddam III has been hang alone. I wonder when George II will follow him ;)

To Kit:
I thought it can be solved without Voronoi's diagram, too. But I got Wrong Answer here. Could you send your solution to gaoyihan@gmail.com? I want to check my program. you can only give me the exe-file.

Edited by author 11.01.2007 16:24

I think it's binary search + Monte-Carlo. Is such approach correct?

Edited by author 11.01.2007 18:16

Why Monte-Carlo? I think, you'll get WA, because answer should be very accurate. Use binary search and bruteforce - O(N^3*logN), AC in ~ 0.25 secs.

I think it's like this. The problem is how to define if for the given radius r the original circle is completely covered? (I don't think that there is a straight formula for 300 points). Therefore I just generate 50 points randomly and for each check does it belong to one of the inner circles or not. If there is a point that does not belong to any of the inner circle, the radius is not big enough, otherwise it's big enough. The binary search is obvious. How do you check the coverage with bruteforce? Any hint or algo?