pku 2398[计算几何]

pku 2398[计算几何]

//和2318差不多，只是输入的board是无序的，输出是玩具数为t(>0)的箱子数(>0)

#include < iostream >
#include < stdlib.h >
using   namespace  std;
#define  MAXN 5000+1
#define  eps 1e-8
#define  _sign(x) ((x)>eps?1:((x)<-eps?2:0))

struct  point {int x,y;} ;
struct  line {point a,b;} ;

int  ans[MAXN];
line board[MAXN];

double  xmult(point p0,point p1,point p2) {//叉积，囧
    return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);
}
int  cmp( const   void   * a, const   void   * b)
{
    line *aa=(line*)a,*bb=(line*)b;
    if(aa->a.x == bb->a.x) 
        return aa->b.x - bb->b.y;
    else return aa->a.x - bb->a.x;
}
int  main()
{
    int n,m,x1,y1,x2,y2,u1,u2,i;
    point toys;
    while(scanf("%d",&n)!=EOF && n )
    {
        memset(ans,0,sizeof(ans));
        scanf("%d%d%d%d%d",&m,&x1,&y1,&x2,&y2);
        for(i=0;i<n;i++)
        {
            scanf("%d%d",&u1,&u2);
            board[i].a.x=u1;
            board[i].a.y=y1;
            board[i].b.x=u2;
            board[i].b.y=y2;
        }
        qsort(board,n,sizeof(board[0]),cmp);
        board[n].a.x=x2;
        board[n].a.y=y1;
        board[n].b.x=x2;
        board[n].b.y=y2;
        for(i=0;i<m;i++)
        {
            scanf("%d%d",&(toys.x),&(toys.y));
            int low=0,hig=n,mid;
            while(low+1<hig)
            {
                mid=(low+hig)>>1;
                double res=xmult(board[mid].a,board[mid].b,toys);
                if(res>0) low=mid;
                else hig=mid;
            }
            if(xmult(board[low].a,board[low].b,toys)<0) ans[low]++;
            else  ans[low+1]++;
        }
        printf("Box\n");
        int t=1,c;
        for(t=1;t<=m;t++)
        {
            for(i=0,c=0;i<=n;i++)
            {
                if(ans[i]==t) 
                {
                    c++;
                    ans[i]=0;
                }
            }
            if(c>0)
                printf("%d: %d\n",t,c);
            m=m-c*t;
        }
        
    }
    return 0;
}