Hi all, I am currently thinking about an interesting geometry problem: Give N point (xi,yi) find a circle that it eclose at least 3 points and its radius is minium as possible. Print the result exactly 5 digits after the dot. I can solve the easy version of it with the limits 3<=N<=1000 and -30000<=xi,yi<=30000: http://vn.spoj.com/problems/TRIPOD/ But wth the hard version 3<=N<=100000 and -2100000000<=xi,yi<=2100000000: http://vn.spoj.com/problems/TRIPOD2/ I have no idea, can anyone show me the way to solve it?

Hi all, I am currently solving a problem that must find the number of different sub seqence of a array that elements can appear more than one example 3 3 5 6. I think the answer is ((number of 1)+1)*((number of 2)+2)*... like 3 3 5 has (2+1)*(5+1)=6 different sub sequences. But it's wrong: 3 5 3 has 7 different sub sequences. Any one help me,please?

Link to the problem.