Segment set

 1 #include<iostream>
 2 using namespace std;
 3 static int set[1005];
 4 static int num[1005];
 5 struct point{
 6     double x, y;
 7 };
 8 struct edge{
 9     point a, b;
10 }e[1005];
11 double cross(point a,point b,point c){//三点的叉乘  
12     return (b.x-a.x)*(c.y-a.y)-(b.y-a.y)*(c.x-a.x);  
13 } 
14 bool OnSegment(point a,point b,point c){//判断是否有重叠   
15     return c.x>=min(a.x,b.x)&&c.x<=max(a.x,b.x)&&c.y>=min(a.y,b.y)&&c.y<=max(a.y,b.y);  
16 }
17 
18 bool intersect(point a,point b,point c,point d) //判断是否相交  
19 {  
20     double d1,d2,d3,d4;  
21     d1 = cross(c, d, a);  
22     d2 = cross(c, d, b);  
23     d3 = cross(a, b, c);  
24     d4 = cross(a, b, d);  
25     if(d1 * d2 < 0 && d3 * d4 < 0)  return 1;  
26     else if(d1 == 0 && OnSegment(c,d,a)) return 1;  
27     else if(d2 == 0 && OnSegment(c,d,b)) return 1;  
28     else if(d3 == 0 && OnSegment(a,b,c)) return 1;  
29     else if(d4 == 0 && OnSegment(a,b,d)) return 1;  
30     return 0;  
31 }
32 
33 int find(int x){
34     int temp = x;
35     while( set[temp] != temp ){
36         temp = set[temp];
37     }
38     int root = temp;
39     temp = x;
40     while(set[temp] != root){
41         int t = temp;
42         temp = set[temp];
43         set[t] = root;
44     }
45     return root;
46 }
47 
48 void merge(int x, int y){
49     int fx = find(x);
50     int fy = find(y);
51     if(fx < fy){
52         set[fy] = fx;
53         num[fx] += num[fy];
54     }
55     else if(fx > fy){
56         set[fx] = fy;
57         num[fy] += num[fx];
58     }
59 }    
60 int main(int argc, char const *argv[]){    
61     int t, n;
62     cin >> t;
63     while(t--){
64         cin >> n;
65         
66         int k = 0;
67         for(int i = 0; i <= n; i++){
68             set[i] = i;
69             num[i] = 1;
70         }
71 
72         while(n--){
73             string s;
74             cin >> s;
75             if(s == "P"){
76                 k++;
77                 cin >> e[k].a.x >> e[k].a.y >> e[k].b.x >> e[k].b.y;
78                 for(int j = 1; j <= k; j++){
79                     if(find(k) != find(j) && intersect(e[k].a, e[k].b, e[j].a, e[j].b)) {
80                      merge(k,j); 
81                      //break; 
82                     }  
83                 }
84             }
85             else if(s == "Q"){
86                 int m;
87                 cin >> m;
88                 cout << num[find(m)] << endl;
89             }
90             
91         }
92         if(t) cout << endl;
93     }
94     
95     return 0;
96 }