[恢]hdu 2056

2011-12-15 05:02:51

地址：http://acm.hdu.edu.cn/showproblem.php?pid=2056

题意：给2个矩阵的对角线坐标，求相交面积。计算几何。

代码：

# include <stdio.h>


double max(double a, double b){return a>b?a:b;}
double min(double a, double b){return a<b?a:b;}


double gao(double a, double b, double c, double d)
{
    double x = max(a,c) ;
    double y = min(b,d) ;
    y -= x ;
    return max(y,0) ;
}


int main ()
{
    double t[2], b[2], l[2], r[2] ;
    double x1,y1,x2,y2,x3,y3,x4,y4 ;
    while (~scanf ("%lf%lf%lf%lf%lf%lf%lf%lf", 
            &x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4))
    {
        t[0] = min(y1,y2) ;
        t[1] = min(y3,y4) ;
        
        b[0] = max(y1,y2) ;
        b[1] = max(y3,y4) ;
        
        l[0] = min(x1,x2) ;
        l[1] = min(x3,x4) ;
        
        r[0] = max(x1,x2) ;
        r[1] = max(x3,x4) ;
        printf ("%.2lf\n", gao(t[0],b[0],t[1],b[1]) * 
                            gao(l[0],r[0],l[1],r[1])) ;
    }
    return 0 ;
}