Poj Solution 2600

http://poj.org/problem?id=2600

#include <stdio.h>
#include <math.h>
 
const double eps = 1e-4;
const double pi = acos(-1.0);
 
struct TPoint 
{
        double x, y;
}p[60], a[60];
double angle[60];
 
double multi(TPoint p1, TPoint p2, TPoint p0)
{
    return (p1.x - p0.x) * (p2.y - p0.y) - (p2.x - p0.x) * (p1.y - p0.y);
}
 
TPoint fine_a2(TPoint a1, TPoint m, double angle1)
{
    TPoint a2;
    double r, angle2, angle3;
    r = sqrt((a1.x - m.x) * (a1.x - m.x) + (a1.y - m.y) * (a1.y - m.y));
    angle2 = acos((a1.x - m.x) / r);
    if(a1.y < m.y) {
        if(angle2 <= pi / 2) angle2 = -angle2;
        if(angle2 > pi / 2) angle2 = 3 * pi / 2 - (angle2 - pi / 2);
    }
    angle3 = angle2 - angle1;
    a2.x = m.x + r * cos(angle3);
    a2.y = m.y + r * sin(angle3);
    if(multi(m, a2, a1) < 0) return a2;
    angle3 = angle2 + angle1;
    a2.x = m.x + r * cos(angle3);
    a2.y = m.y + r * sin(angle3);
    if(multi(m, a2, a1) < 0) return a2;    
}
 
int main()
{
    int n, i, j;
    while(scanf("%d", &n) != EOF){
        for(i = 0;i < n;i++){
            scanf("%lf%lf", &p[i].x, &p[i].y);
        }
        for(i = 0;i < n;i++){
            scanf("%lf", &angle[i]);
            angle[i] = angle[i] * pi / 180;
        }
        a[0].x = 0;
        a[0].y = 0;
        while(1){
            for(i = 1;i <= n;i++){
                a[i] = fine_a2(a[i - 1], p[i - 1], angle[i - 1]);
            }
            if(fabs(a[n].x - a[0].x) <= eps  
                    && fabs(a[n].y - a[0].y) <= eps) break;
            else {
                a[0].x = (a[0].x + a[n].x) / 2;
                a[0].y = (a[0].y + a[n].y) / 2;
            }
        }
        for(i = 0;i < n;i++){
            printf("%.0lf %.0lfn", a[i].x, a[i].y);
        }        
    }
    return 0;
}