• poj 2540 Hotter Colder 切割多边形


    /*
    poj 2540 Hotter Colder 切割多边形
    
    用两点的中垂线切割多边形,根据冷热来判断要哪一半
    
    然后输出面积
    
    
    */
    #include <stdio.h>  
    #include<math.h>  
    const double eps=1e-8;  
    const int N=200;  
    struct point  
    {  
        double x,y;  
    	point(){}
    	point(double a,double b):x(a),y(b){}
    }dian[N];  
    point jiao[N];
    inline bool mo_ee(double x,double y)  
    {  
        double ret=x-y;  
        if(ret<0) ret=-ret;  
        if(ret<eps) return 1;  
        return 0;  
    }  
    inline bool mo_gg(double x,double y)  {   return x > y + eps;} // x > y  
    inline bool mo_ll(double x,double y)  {   return x < y - eps;} // x < y  
    inline bool mo_ge(double x,double y) {   return x > y - eps;} // x >= y  
    inline bool mo_le(double x,double y) {   return x < y + eps;}    // x <= y  
    inline double mo_xmult(point p2,point p0,point p1)//p1在p2左返回负,在右边返回正  
    {  
        return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);  
    }  
      
    point mo_intersection(point u1,point u2,point v1,point v2)  
    {  
        point ret=u1;  
        double t=((u1.x-v1.x)*(v1.y-v2.y)-(u1.y-v1.y)*(v1.x-v2.x))  
            /((u1.x-u2.x)*(v1.y-v2.y)-(u1.y-u2.y)*(v1.x-v2.x));  
        ret.x+=(u2.x-u1.x)*t;  
        ret.y+=(u2.y-u1.y)*t;  
        return ret;  
    }  
    /////////////////////////  
    //求法向量
    point mo_getfaxian(point xiang)
    {
         	point a;
         	if(mo_ee(xiang.x,0))
         	{
                   	a.x=1;
                   	a.y=0;
                   	return a;
         	}else if(mo_ee(xiang.y,0))
         	{
                   	a.x=0;
                   	a.y=1;
                   	return a;
         	}else
         	{
                   	a.x=1;
                   	a.y=-1.0*xiang.x/xiang.y;
                   	return a;
         	}
     
    }
    
    //求多边形面积  
    double mo_area_polygon(point *dian,int n)  
    {  
        int i;  
        point yuan;  
        yuan.x=yuan.y=0;  
        double ret=0;  
        for(i=0;i<n;++i)  
        {  
            ret+=mo_xmult(dian[(i+1)%n],yuan,dian[i]);  
        }  
    	if(ret<0) ret=-ret;
        return ret/2;  
    }  
    point mo_banjiao_jiao_temp[N*2];  
    void mo_banjiao_cut(point *ans,point qian,point hou,int &nofdian)  
    {  
        int i,k;  
        for(i=k=0;i<nofdian;++i)  
        {  
            double a,b;  
            a=mo_xmult(hou,ans[i],qian);  
            b=mo_xmult(hou,ans[(i+1)%nofdian],qian);  
            if(mo_ge(a,0))//顺时针就是<=0  
            {  
                mo_banjiao_jiao_temp[k++]=ans[i];  
            }if(mo_ll(a*b,0))  
            {  
                mo_banjiao_jiao_temp[k++]=mo_intersection(qian,hou,ans[i],ans[(i+1)%nofdian]);  
            }  
        }  
        for(i=0;i<k;++i)  
        {  
            ans[i]=mo_banjiao_jiao_temp[i];  
        }  
        nofdian=k;  
    }
    int main()
    {
    	point qian(0,0);
    	point cur,mid,end;
    	char order[20];
    	int flag=0;
    	jiao[0]=point(0,0);
    	jiao[1]=point(10,0);
    	jiao[2]=point(10,10);
    	jiao[3]=point(0,10);
    	int jiaodian=4;
    	while(scanf("%lf",&cur.x)!=EOF)
    	{
    		scanf("%lf%s",&cur.y,order);
    		getchar();
    		if(order[0]=='S'||flag==1)
    		{
    			flag=1;
    			printf("0.00
    ");
    			continue;
    		}
    		mid.x=(cur.x+qian.x)/2;
    		mid.y=(cur.y+qian.y)/2;
    		end=mo_getfaxian(point(cur.x-qian.x,cur.y-qian.y));
    		end.x=mid.x+end.x;
    		end.y=mid.y+end.y;
    		bool zai=mo_gg(mo_xmult(end,cur,mid),0);
    		if((order[0]=='H'&&zai)||(order[0]=='C'&&(!zai)))
    		{
    			
    		}else
    		{
    			point tem=end;
    			end=mid;
    			mid=tem;
    		}
    		mo_banjiao_cut(jiao,mid,end,jiaodian);  
    		double area=mo_area_polygon(jiao,jiaodian);
    		printf("%.2lf
    ",area);
    		qian=cur;
    	}
    	return 0;
    }


  • 相关阅读:
    element 树形控件使用
    js粘贴图片并显示
    vue-element Tree树形控件通过id默认选中
    解决win10shift+右键显示在此处打开powershell而不是命令窗口的问题
    maven安装与配置
    解决dos窗口中文乱码问题
    vue单页面应用刷新网页后vuex的state数据丢失的解决方案
    vue 单个倒计时组件
    js将秒转换为时分秒
    vue3.0用vue-awesome-swiper
  • 原文地址:https://www.cnblogs.com/riskyer/p/3249418.html
Copyright © 2020-2023  润新知