摘要：
Vance and Shackler like playing games. One day, they are playing a game called "arcane numbers". The game is pretty simple, Vance writes down a finite 阅读全文
摘要：
解题关键：最大面积即4个点都在其外接圆上时的面积。 $p = (a + b + c + d)/2$ $s = \sqrt {(p - a)(p - b)(p - c)(p - d)}$ 设四边形的四个点分别为A,B,C,D,四条边为a,b,c,d $s = \frac{1}{2}ab\sin \al 阅读全文