poj 2318 TOYS

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<memory.h>
 4 using namespace std;
 5 const int maxn = 5050;
 6 int po[maxn];
 7 
 8 struct point
 9 {
10     int x,y;
11     point(){}
12     point(int a,int b){x = a; y = b;}
13 
14 };
15 
16 point operator +(const point &a,const point &b)
17 {
18     return point(a.x+b.x, a.y+b.y);
19 }
20 
21 point operator -(const point &a,const point &b)
22 {
23     return point(a.x-b.x,a.y-b.y);
24 }
25 
26 int operator ^(const point &a,const point &b)
27 {
28     return a.x*b.y - a.y*b.x;
29 }
30 
31 struct line
32 {
33     point s,e;
34     line(){}
35     line(point A,point B){ s = A; e = B; }
36 };
37 line L[maxn];
38 
39 int Xmulti(point d,point a,point b)   //if (da X db < 0) it is on the left
40 {
41     return (a-d)^(b-d);
42 }
43 
44 
45 int main()
46 {
47     int n,m,x1,y1,x2,y2,ui,li;
48     int step = 0;
49     while(scanf("%d",&n) == 1 && n)
50     {
51         if(step) puts("");
52         step++;
53         memset(po,0,sizeof(po));
54         scanf("%d%d%d%d%d",&m,&x1,&y1,&x2,&y2);
55         for(int i = 0; i < n; i++)
56         {
57             scanf("%d%d",&ui,&li);
58             L[i] = line(point(ui,y1),point(li,y2));
59         }
60         L[n] = line(point(x2,y1),point(x2,y2));
61         int x,y;
62         while(m--)
63         {
64             scanf("%d%d",&x,&y);
65             point d =point(x,y);
66             int l = 0,r = n,t;
67             while(l <= r)
68             {
69                 int mid = (l + r) / 2;
70                 if(Xmulti(d,L[mid].s,L[mid].e) < 0)  //<0 on the left
71                 {
72                     t = mid;
73                     r = mid - 1;
74                 }
75                 else l = mid + 1;
76             }
77             po[t]++;
78         }
79         for(int i = 0; i <= n;i++)
80             printf("%d: %d\n",i,po[i]);
81     }
82     return 0;
83 }