#pragma GCC optimize("Ofast")
With this line of code I'm getting AC 0.468, without it I'm getting TL14

For each pair of points, consider the family of lines parallel to the line that connects the points. Project all the points on the line perpendicular to the family, sort the coordinate, and find the smallest coordinate distance that covers k points.

Test 16 contains the special case, where n = k = 1.
The answer is obviously 0.000000.

I don't understand why the author has put this special case on test 16, I didn't ever think, that it could be a special case.
It rather costs me lots of time to debug.

... then maybe you misread the statement:
1. Pins have diameter 1, not 0
2. You should output diameter of the ball, not radius

Edit: Found it, just print out the solution as fixed.
E.g. cout<<fixed<<solution;

Edited by author 19.04.2011 05:59

I have WA 4. Can somebody give me a hint about what's in this test case?

Can I get any hint on how test 21 looks like, I'm going crazy with WA on that one...

Edited by author 16.04.2011 04:33

Can someone explain sample test?
How come output is 1.00000000, when there is a pin at (3,0)?

Im using the most stupid algo n^4
With special case m<=2
What`s the trick?

Any hints on how to solve this problem??

Edited by author 09.04.2011 01:59

In the final loop, when you count the number of circles which the given line touches, use only + and * operations (without divisions and - OMG - square roots) - this will speed your code up several times.

Edited by author 13.10.2010 21:13

I wrote a solution with complexity of O(n^3 log n) and got AC for 0.75 sec. Is there a solution for O(n^3) or O(n^2 log n)?

Can anyone help me, I got WA on test 2 and don't understand why?

Edited by author 09.10.2010 14:34