OJ-Problems-Source/HDOJ/3712_autoAC.cpp

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#include<cstdio>
#include<iostream>
#include<complex>
#include<cmath>
using namespace std;
#define Y imag
#define X real
const double eps = 1e-9;
const char *err = "Error";
const double pi = acos(-1.0);
typedef complex<double> pnt;
static double dot(const pnt &a, const pnt& b) {return X(conj(a)*b);}
static double cross(const pnt &a, const pnt &b) {return imag(conj(a)*b);}
void work(const pnt& s, double argu) {
while(argu<0) argu+=2*pi;
while(argu >= 2*pi) argu -=2*pi;
if(argu < pi+eps) {
puts(err);
return ;
}
argu = - argu;
printf("%.3lf\n", X(s) +( abs(argu + 3*pi/2)<eps ? 0 : Y(s)/tan(argu) ));
}
pnt jdg(const pnt& p0, const pnt& p1,const pnt& p3, const pnt& p2){
if(cross(p3-p0,p1-p0) * cross(p2-p0,p1-p0) > -eps) return p0;
double s1 = cross(p2-p1,p0-p1), s2 = cross(p3-p1,p0-p1);
s1 = abs(s1), s2 = abs(s2);
double x = (X(p2) *s2 + X(p3)*s1) / (s1+ s2);
double y = (Y(p2) *s2 + Y(p3)*s1) / (s1+ s2);
pnt p(x,y);
if(cross(p3-p2,p1-p2)*cross(p3-p2,p0-p2)>0 && abs(p-p0) < abs(p-p1)) return p0;
return p;
}
double cal(double arg0, double arg1, double tmp) {
double t1 =arg1+pi/2-(arg0+pi);
double s1 = sin(t1);
double s2 = s1/tmp;
if(s2>=1.0 || s2 <=-1.0) return 1e10;
else return arg1-pi/2-asin(s2);
}
int main(){
int tst;
double tmp;
cin >> tst;
pnt p[3];
while(tst--) {
double x1,y1,x2,y2;
while(cin >> x1 >> y1 >> x2 >> y2){
pnt p1(x1,y1), p2(x2,y2), p0;
int s = -1;
double mx = 1e10;
for(int i=0;i<3;i++){
cin >> x1 >> y1;
p[i] = pnt(x1,y1);
}
cin >> tmp;
for(int i=0;i<3;i++) {
pnt P = jdg(p1,p2,p[i],p[(i+1)%3]);
if(P == p1) continue;
double v = abs(p1-P);
if(v < mx) mx = v, s = i, p0 = P;
}
if(s == -1){
work(p1, arg(p2-p1));
continue;
}
pnt p3;
double t = 0;
if(cross(p2-p1, p[(s+1)%3] - p[s])<0)t = pi;
double arg0 = cal(arg(p2-p1),arg(p[(s+1)%3] - p[s])+t,tmp);
pnt np = pnt(X(p0) + 200*cos(arg0), Y(p0) + 200*sin(arg0));
int k = -1;
for(int i=0;i<3;i++) {
if(i==s) continue;
pnt P = jdg(p0,np,p[i],p[(i+1)%3]);
if(P == p0) continue;
k = i;p3 = P;
}
t = 0;
if(cross(p3-p0, p[(k+1)%3] - p[k])<0)t = pi;
double arg1 = cal(arg(p3 - p0), arg(p[(k+1)%3] - p[k])+t, 1.0/tmp);
if(arg1 == 1e10) {
puts(err);
continue;
}
work(p3,arg1);
}
}
}