F_13th的博客

点的定义 struct Point{ double x,y; Point(double x=0,double y=0):x(x),y(y){} }; 向量的定义 typedef Point Vector; 运算 加减乘除 Point operator + (Point A,Point B){ return Point(A.x+B.x,A.y+B.y); } Point operator - (Point A,Point B){ return Point(A.x-B.x,

常量 const double inf=1e100; const double eps=1e-8; const double pi=acos(-1.0); 函数 int sgn(double x){ if(fabs(x)<eps) return 0; if(x>0) return 1; return -1; } 浮点误差 doubledoubledouble使用%lf\% lf%lf输入，%f\% f%f输出 尽量将除法转化为除法，减少误差 不能直接使用等号判断两个浮