求割点，还要判断割点把图分为几部分

WA了N次，if(!vs[v])chil[x]++是错误的，应为if(!vs[v]){...... if(dfn[x]<=low[v])child[x]++;

代码：

#include
     
      #include
      
       #include
       
        #include
        
         #define nMAX 1005using namespace std;int map[nMAX][nMAX],dfn[nMAX],low[nMAX],cnt[nMAX];int times,root,n,MIN,MAX;int min(int a,int b){    return a
         
          b?a:b;}void init(){    times=0;    memset(dfn,0,sizeof(dfn));    memset(low,0,sizeof(low));    memset(cnt,0,sizeof(cnt));    memset(map,0,sizeof(map));}void tarjan(int u,int fa){    int son=0;    dfn[u]=low[u]=++times;    int v;    for(v=MIN;v<=MAX;v++)    {        //邻接矩阵的就得考虑是否连通！！！        if(!map[u][v])continue;        if(!dfn[v])        {            tarjan(v,u);            low[u]=min(low[u],low[v]);           // if(dfn[u]<=low[v])           //如果下面的cnt[u]++;改成son-1的话，上面的if必须加上                son++;            if(u==root&&son>=2)cnt[u]++;            if(u!=root&&dfn[u]<=low[v])cnt[u]++;        }        else if(v!=fa)low[u]=min(low[u],dfn[v]);    }}int main(){   int i,j,CASE=0;   while(~scanf("%d",&i)&&i)   {       CASE++;       MIN=nMAX,MAX=-1;       init();       MIN=min(MIN,i);       MAX=max(MAX,i);       scanf("%d",&j);       MIN=min(MIN,j);       MAX=max(MAX,j);       map[i][j]=map[j][i]=1;       while(~scanf("%d",&i)&&i)       {           MIN=min(MIN,i);           MAX=max(MAX,i);           scanf("%d",&j);           MIN=min(MIN,j);           MAX=max(MAX,j);           map[i][j]=map[j][i]=1;       }       bool fg=0;       root=MIN;       tarjan(MIN,-1);       printf("Network #%d\n",CASE);       for(i=MIN;i<=MAX;i++)       {           if(!cnt[i])continue;           fg=1;           printf("  SPF node %d leaves %d subnets\n",i,cnt[i]+1);       }       if(!fg)printf("  No SPF nodes\n");       printf("\n");   }   return 0;}