TOJ ： 1414. Temple of Dune

题目：http://acm.tju.edu.cn/toj/showp1414.html

#include <cstdio>
#include <cmath>
#include <iomanip>
#define PI acos(-1)
#define eps 1e-5
using namespace std;

int main(){
    int cas;
    double x1, y1, x2, y2, x3, y3;
    scanf("%d", &cas);
    while (cas--) {
        scanf("%lf%lf%lf%lf%lf%lf", &x1, &y1, &x2, &y2, &x3, &y3);
        double S = abs(x1 * y2 + x2 * y3 + x3 * y1 - x2 * y1 - x3 * y2 - x1 * y3) * 0.5;
        double a = sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
        double b = sqrt((x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3));
        double c = sqrt((x3 - x1) * (x3 - x1) + (y3 - y1) * (y3-y1));
        double R = a * b * c / (4 * S);
        double A = 2 * asin(a / (2 * R));
        double B = 2 * asin(b / (2 * R));
        //double C = 2 * asin(c / (2 * R));        
        for(int i = 3; i < 201; i++) {
            double t1 = A * i / (2 * PI);
            double t2 = B * i / (2 * PI);
            if(abs(t1 - (int)t1) < eps && abs(t2 - (int)t2) < eps) {
                printf("%d\n", i);
                break;
            }
        }
    }
}