public class Corridor {
    double t1,t2;
    int i1,i2;

    public Corridor() {}

    /***this is positive iff there is a billiard path*/

    public void compute(String W,ListenTriangle[] T3,int n) {
	i1=0;
	i2=0;
	int digit=0;

	/*first compute top*/
	double top=100000;
	double yy=100000.0;
	String S=new String();
	for(int i=0;i<n;++i) {
	S=W.substring(i,i+1);
	if(S.compareTo("1")==0) digit=1;
	if(S.compareTo("2")==0) digit=2;
	if(S.compareTo("3")==0) digit=3;
	if((digit==1)&&(i%2==0)) yy=T3[i].z[1].y;
	if((digit==2)&&(i%2==0)) yy=T3[i].z[2].y;
	if((digit==3)&&(i%2==0)) yy=T3[i].z[0].y;
	if((digit==1)&&(i%2==1)) yy=T3[i].z[2].y;
	if((digit==2)&&(i%2==1)) yy=T3[i].z[0].y;
	if((digit==3)&&(i%2==1)) yy=T3[i].z[1].y;
	if(top>yy) {top=yy;t1=top;i1=i;}
	}


	double bot=-100000;
	yy=-100000.0;

	for(int i=0;i<n;++i) {
	S=W.substring(i,i+1);
	if(S.compareTo("1")==0) digit=1;
	if(S.compareTo("2")==0) digit=2;
	if(S.compareTo("3")==0) digit=3;
	if((digit==1)&&(i%2==1)) yy=T3[i].z[1].y;
	if((digit==2)&&(i%2==1)) yy=T3[i].z[2].y;
	if((digit==3)&&(i%2==1)) yy=T3[i].z[0].y;
	if((digit==1)&&(i%2==0)) yy=T3[i].z[2].y;
	if((digit==2)&&(i%2==0)) yy=T3[i].z[0].y;
	if((digit==3)&&(i%2==0)) yy=T3[i].z[1].y;
	if(bot<yy) {bot=yy;t2=bot;i2=i;}
	}

    }

    public Corridor computePair(String W,ListenTriangle[] T3,int n) {
	int digit=0;
	Corridor C=new Corridor();
	C.i1=i1;
	C.i2=i2;
	double yy=0;
	String S=new String();

	int i = i1;
	S=W.substring(i,i+1);
	if(S.compareTo("1")==0) digit=1;
	if(S.compareTo("2")==0) digit=2;
	if(S.compareTo("3")==0) digit=3;
	if((digit==1)&&(i%2==0)) yy=T3[i].z[1].y;
	if((digit==2)&&(i%2==0)) yy=T3[i].z[2].y;
	if((digit==3)&&(i%2==0)) yy=T3[i].z[0].y;
	if((digit==1)&&(i%2==1)) yy=T3[i].z[2].y;
	if((digit==2)&&(i%2==1)) yy=T3[i].z[0].y;
	if((digit==3)&&(i%2==1)) yy=T3[i].z[1].y;
	C.t1=yy;

	i=i2;
	S=W.substring(i,i+1);
	if(S.compareTo("1")==0) digit=1;
	if(S.compareTo("2")==0) digit=2;
	if(S.compareTo("3")==0) digit=3;
	if((digit==1)&&(i%2==1)) yy=T3[i].z[1].y;
	if((digit==2)&&(i%2==1)) yy=T3[i].z[2].y;
	if((digit==3)&&(i%2==1)) yy=T3[i].z[0].y;
	if((digit==1)&&(i%2==0)) yy=T3[i].z[2].y;
	if((digit==2)&&(i%2==0)) yy=T3[i].z[0].y;
	if((digit==3)&&(i%2==0)) yy=T3[i].z[1].y;
	C.t2=yy;
	return(C);
    }
}