link: http://codeforces.com/gym/100803

seems test cases are too weak::

I just try to find floating solution of (a1*x1+a2*x2+...+an*xn)*(b1*x1+b2*x2+...+bn*xn)*(c1*x1+c2*x2+...+cn*xn)... x1+x2+...+xn==k 0<=xi<=1 and it is equal to integer solution for all test cases.. so we have O(polynomial) solution to find minmum floating value of f(x1,x2,....,xn)=(a1*x1+a2*x2+...+an*xn)*(b1*x1+b2*x2+...+bn*xn)*(c1*x1+c2*x2+...+cn*xn) x1+x2+...+xn==k 0<=xi<=1 all of x[] is integers

Hope admin can add test cases....