POJ 1144 Network

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<algorithm>
using namespace std;

char s[1000000];
int n,u,v,tot,len,sum;
const int INF=0x7FFFFFFF;
const int MAXN=105;
vector<int>G[MAXN];
int fail[MAXN],flag[MAXN];

void DFS(int now)
{
    int i;
    for(i=0; i<G[now].size(); i++)
    {
        if(!flag[G[now][i]]&&!fail[G[now][i]])
        {
            flag[G[now][i]]=1;
            DFS(G[now][i]);
        }
    }
}

int main()
{
    int i,ii;
    while(~scanf("%d",&n)&&n)
    {
        for(i=0; i<=n; i++) G[i].clear();
        memset(flag,0,sizeof(flag));
        memset(fail,0,sizeof(fail));
        while(gets(s))
        {
            if(strcmp(s,"0")==0) break;
            len=strlen(s);
            u=INF;
            sum=0;
            for(i=0; i<=len; i++)
            {
                if(s[i]==‘ ‘||s[i]==‘\0‘)
                {
                    if(u==INF) u=sum,sum=0;
                    else
                    {
                        v=sum,sum=0;
                        G[u].push_back(v);
                        G[v].push_back(u);
                    }
                }
                else sum=sum*10+s[i]-‘0‘;
            }
        }


        memset(fail,0,sizeof(fail));
        
        int AAA,ans=0;
        for(ii=1; ii<=n; ii++)
        {
            fail[ii]=1;
            AAA=0;
            memset(flag,0,sizeof(flag));
            for(i=1; i<=n; i++)
            {
                if(fail[i]) continue;
                if(!flag[i])
                {
                    flag[i]=1;
                    DFS(i);
                    AAA++;
                }
            }
            if(AAA!=1) ans++;
            fail[ii]=0;
        }
        printf("%d\n",ans);
    }
    return 0;
}