太慢 >>> import time >>> t=time.time();S([(5,2),(13,2),(17,2)]);print(time.time()-t) 404600 30.230719566345215

@lt 圆上的整点 http://hzwer.com/1457.html

@lt https://vdisk.weibo.com/s/C3AWjT1Hga_zb

关于圆周上格点个数的讨论 https://m.doc88.com/p-0813160423676.html

设四边形的四顶点分别是abcd,根据圆的曲线方程每个点的x^2+y^2=r^2,每条边的长度平方=(x1-x2)^2+(y1-y2)^2=x1^2+y1^2+x2^2+y2^2-2(x1*x2+y1*y2)，四条边的平方和等于8*r^2,即(x1*x2+y1*y2)+(x2*x3+y2*y3)+(x3*x4+y3*y4)+(x4*x1+y4*y1)=0