题目链接:http://poj.org/problem?id=2236

注意:题目中说的是 1~n,所以,在初始化根节点的时候不要弄成 0 ~ n-1这种(for(int i = 0;i < n;i++) 这种是不对的,如果这样,则造成n没有对应的根节点,因为初始化的时候根本没有初始化到n

1 #include
     
       2 #include
      
        3 #include
       
         4 #include
        
          5 using namespace std; 6  7 const int maxn = 1010; 8  9 struct node {10     int x,y;11     bool open;12 }arr[maxn];13 int f[maxn];14 int n,d;15 16 void Init(int n) {17     for(int i = 1;i <= n;i++)18         f[i] = i;19 }20 21 int FindRoot(int x) {22     if(x == f[x])23         return x;24     f[x] = FindRoot(f[x]);25     return f[x];26 }27 28 double Count(node a,node b) {29     return sqrt(pow(a.x - b.x,2) + pow(a.y - b.y,2));30 }31 32 void Union(int x) {33     int a = FindRoot(x);34     for(int i = 1;i <= n;i++) {35         int b = FindRoot(i);36         if(arr[i].open && Count(arr[i],arr[x]) <= d)37             f[b] = a;38     }39 }40 41 int main() {42     while(scanf("%d%d",&n,&d) != EOF) {43         Init(n);44         for(int i = 1;i <= n;i++) {45             scanf("%d%d",&arr[i].x,&arr[i].y);46             arr[i].open = false;47         }48         char ch;49         int x,y;50         while(cin>>ch) {51             if(ch == 'O') {52                 scanf("%d",&x);53                 arr[x].open = true;54                 Union(x);55             }56             else {57                 scanf("%d%d",&x,&y);58                 if(FindRoot(x) == FindRoot(y))59                     printf("SUCCESS\n");60                 else61                     printf("FAIL\n");62             }63         }64     }65     return 0;66 }