hdu-1071

无节操，贴个别人的代码

//抛物线 yp=a*(x-b)^2+c;//直线 yz=k*x+s;//二重积分公式： f(x0,x1)(yp-yz)*dx;#include<iostream>using namespace std;double a,b,c,k,s;double fun(double x){return 1.0*(a*x*x*x/3)-1.0*(a*b+k/2)*x*x+(a*b*b+c-s)*x;}int main(){int t;double x1,y1,x2,y2,x3,y3;scanf("%d",&t);while(t--){scanf("%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3);k=(y3-y2)/(x3-x2);s=y3-k*x3;a=(y2-y1)/((x2-x1)*(x2-x1));b=x1;c=y1;double area=1.0*(fun(x3)-fun(x2));printf("%.2lf\n",area);}return 0; }