因为一无所有，所以拥有无限可能。

原题题面 Given three concentric circles whose radiuses are r1r_1r1​,r2r_2r2​,r3r_3r3​respectively, and A,B,CA,B,CA,B,C are the moving points on the given three circles respectively. Determine the expected area of △ABC\triangle ABC△ABC . 输入描述 The first line con

原题题面 Given nnn points in 2D plane. Considering all circles that the origin point (0,0)(0,0)(0,0) is on their boundries, find the one with the maximum given points on its boundry. Print the maximum number of points. 输入描述 The first line contains one integer