UVA11437

题目：

In the picture below you can see a triangle ABC. Point D, E and F divides the sides BC, CA and AB into ratio 1:2 respectively. That is CD=2BD, AE=2CE and BF=2AF. A, D; B, E and C, F are connected. AD and BE intersects at P, BE and CF intersects at Q and CF and AD intersects at R.

So now a new triangle PQR is formed. Given triangle ABC your job is to find the area of triangle PQR.

代码：

#include <iostream>
#include <stdio.h>
#include <math.h>
using namespace std;
int main(){
//    freopen("in.txt", "r", stdin);
    int n;
    scanf("%d", &n);
    int id = 1;
    for(; id<=n; id++){
        double ax, ay, bx, by, cx, cy;
        cin >> ax >> ay >> bx >> by >> cx >> cy;
        double a = sqrt((bx-cx)*(bx-cx)+(by-cy)*(by-cy));
        double b = sqrt((ax-cx)*(ax-cx)+(ay-cy)*(ay-cy));
        double c = sqrt((ax-bx)*(ax-bx)+(ay-by)*(ay-by));
        double p = (a+b+c)/2;
        double area = sqrt(p*(p-a)*(p-b)*(p-c))/7;
        int ans = floor(area+0.5);
        cout << ans << endl;
    }
    return 0;
}