杭电ACM1071The area---------求积分面积

#include <iostream>#include <stdio.h>using namespace std;int main(){   int t;    double x1,y1,x2,y2,x3,y3,a,k,s;    cin>>t;    while(t--)    { cin>>x1>>y1>>x2>>y2>>x3>>y3;      a=(y2-y1)/((x2-x1)*(x2-x1));      k=(y2-y3)/(x2-x3);      s=a/3*(x3*x3*x3-x2*x2*x2)+(a*x1*x1+k*x3+y1-y3)*(x3-x2)+0.5*(2*a*x1+k)*(x2*x2-x3*x3);       printf("%.2f\n",s);    }return 0;}