【HDU2120】Ice_cream's world I（并查集基础题）

查环操作，裸题。一次AC。

 #include <iostream>
 #include <cstring>
 #include <cstdlib>
 #include <cctype>
 #include <cmath>
 #include <string>
 #include <cstdio>
 #include <algorithm>
 #include <numeric>
 using namespace std;

 const int maxnn = 1e4 + ;
 int cnt = , father[maxnn];

 int getFather (int x) {
     if (father[x] != x) {
         father[x] = getFather (father[x]);
     }
     return father[x];
 }

 void Union (int p, int q) {
     int x = getFather (p);
     int y = getFather (q);
     if (x != y) {
         father[y] = x;
     } else {
         cnt ++;
     }
 }

 int main () {
     int n, x;
     while (cin >> n >> x) {
         for (int i = ; i < x; ++ i) {
             father[i] = i;
         }
         cnt = ;
         for (int i =  ;i < x; ++ i) {
             int p, q; scanf("%d%d", &p, &q);
             Union (p, q);
         }

         /*for (int i = 0; i < n; ++ i) {
             if (getFather (i) == i) {
                 ans ++;
             }
         }*/
         cout << cnt << endl;
     }
     return ;
 }