Floyd联通， 然后为了输出联通分量而新建一个图， 让互相可以打电话的建立一条边， 然后dfs输出联通分量就ok了。
#include<cstdio>
#include<iostream>
#include<cstring>
#include<string>
#include<map>
#include<vector>
#define REP(i, a, b) for(int i = (a); i < (b); i++)
using namespace std;const int MAXN = 30;
int d[MAXN][MAXN], g[MAXN][MAXN], vis[MAXN], n, m;
map<string, int> id;
vector<string> word;int get_id(string s)
{if(id.count(s)) return id[s];word.push_back(s);return id[s] = word.size() - 1; //注意这里要减去1
}void print(int u, int p)
{if(p != 1) printf(", ");cout << word[u];vis[u] = 1;REP(v, 0, n)if(g[u][v] && !vis[v])print(v, 0);
}int main()
{int kase = 0;while(~scanf("%d%d", &n, &m) && n && m){if(kase) puts("");word.clear(); id.clear();memset(d, 0, sizeof(d));memset(vis, 0, sizeof(vis));memset(g, 0, sizeof(g));while(m--){string a, b;cin >> a >> b;d[get_id(a)][get_id(b)] = 1;}REP(k, 0, n)REP(i, 0, n)REP(j, 0, n)d[i][j] = d[i][j] || (d[i][k] && d[k][j]);REP(i, 0, n)REP(j, 0, n)g[i][j] = (d[i][j] && d[j][i]);printf("Calling circles for data set %d:\n", ++kase);REP(i, 0, n)if(!vis[i]){print(i, 1);puts("");}}return 0;
}