weiwancheng

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <map>
 5 using namespace std;
 6 
 7 const int maxn = 1005;
 8 struct Node {
 9     int id, x, y;
10 }init[maxn], node[maxn], ans[maxn];
11 
12 
13 int n, top;
14 int G[maxn][maxn];
15 int cross(Node n1, Node n2, Node n3) {
16     return (n2.x - n1.x) * ( n3.y - n1.y ) - (n3.x - n1.x) * (n2.y - n1.y);
17 }
18 
19 bool cmp(Node p1, Node p2) {
20     if(p1.x != p2.x) {
21         return p1.x < p2.x;
22     }
23     return p1.y < p2.y;
24 }
25 
26 void conext() {
27     sort(node + 1 + 1, node + n + 1, cmp);
28     top = 0;
29     ans[top++] = node[1];
30     for(int i = 2; i <= n; i++) {
31         while(top > 1 && cross(ans[top - 2], ans[top - 1], node[i]) <= 0 && G[ans[top-1].id][i]) {
32             top--;
33         } 
34         ans[top++] = node[i];
35     }
36     int k = top;
37     for(int i = n - 1; i >= 2; i--) {
38         while(top > k && cross(ans[top - 2], ans[top - 1], node[i]) >= 0 && G[ans[top-1].id][i]) {
39             top --;
40         }
41         ans[top++] = node[i];
42     }
43     if(top > 1) top--;
44 }
45 
46 int main() {
47     int n;
48     while(EOF != scanf("%d",&n) ) {
49         for(int i = 1; i <= n; i++) {
50             scanf("%d %d %d",&init[i].id, &init[i].x, &init[i].y);
51         }
52         memset(G, 0, sizeof(G));
53         for(int i = 1; i <= n i++) {
54             for(int j = 1; j <= 4; j++) {
55                 scanf("%d",&v);
56                 G[i][v] = G[v][i] = 1;
57             }
58         }
59         for(int i = 1; i <= n; i++) {
60             for(int j = 0; j < n; j++) {
61                 int x = ( i + j ) % n;
62                 if(x == 0) x = n; 
63                 node[x] = init[j + 1];
64             }
65             conext();
66             for(int i = 0; i < top; i++) {
67                 printf("%d ", ans[i].id);
68             } puts("");
69         }
70     }
71     return 0;
72 }