LA 3644 易爆物

https://vjudge.net/problem/UVALive-3644

简单的并查集题目。

 #include<iostream>
 using namespace std;

 const int maxn =  + ;

 int p[maxn];

 int find(int x)
 {
     return p[x] != x ? p[x] = (find(p[x])) : x;
 }

 int main()
 {
     //freopen("D:\\txt.txt", "r", stdin);
     int x, y;
     while (cin >> x && x != -)
     {
         for (int i = ; i < maxn; i++)
             p[i] = i;
         int cnt = ;
         while (x != -)
         {
             cin >> y;
             x = find(x);
             y = find(y);
             if (x == y)   cnt++;
             else p[x] = y;
             cin >> x;
         }
         cout << cnt << endl;
     }
 }