求一个图中割点数目（模板题）


主要是输入的细节，处理好回车结束符和最末尾的0就好了


#include<iostream>
#include<cstdio>
#include<stdio.h>
#include<cstdlib>
#include<stdlib.h>
#include<algorithm>
#include<string.h>
#include<cstring>
using namespace std;

const int maxn=1010;
const int maxm=10010;
struct Edge{
    int to,nxt;
    bool cut;
}edge[maxm];
int head[maxn],tot;
int Low[maxn],DFN[maxn],Stack[maxn];
int Index,top,block;
bool Instack[maxn];
bool cut[maxn];
int add_block[maxn];
int bridge;

void addedge(int u,int v){
    edge[tot].to=v;
    edge[tot].nxt=head[u];
    edge[tot].cut=false;
    head[u]=tot++;
}

void Tarjan(int u,int pre){
    int v;
    Low[u]=DFN[u]=++Index;
    Stack[top++]=u;
    Instack[u]=true;
    int son=0;
    int pre_cnt=0;
    for(int i=head[u];i!=-1;i=edge[i].nxt){
        v=edge[i].to;
        if (v==pre&&pre_cnt==0){
            pre_cnt++;
            continue;
        }
        if (!DFN[v]){
            son++;
            Tarjan(v,u);
            if (Low[u]>Low[v]) Low[u]=Low[v];
            if (Low[v]>DFN[u]){
                bridge++;
                edge[i].cut=true;
                edge[i^1].cut=true;
            }
            if (u!=pre&&Low[v]>=DFN[u]){
                cut[u]=true;
                add_block[u]++;
            }
        }
        else if (Low[u]>DFN[v])
            Low[u]=DFN[v];
    }
    if (u==pre&&son>1) cut[u]=true;
    if (u==pre) add_block[u]=son-1;
    Instack[u]=false;
    top--;
}

void init(){
    memset(DFN,0,sizeof(DFN));
    memset(Instack,0,sizeof(Instack));
    memset(add_block,0,sizeof(add_block));
    memset(cut,false,sizeof(cut));
    memset(head,-1,sizeof(head));
    Index=top=0;tot=0;
}

int main(){
    //freopen("input.txt","r",stdin);
    int u,v,n;
    while(scanf("%d",&n),n){
        init();
        while(scanf("%d",&u),u){
            while(getchar()!='\n'){
                scanf("%d",&v);
                addedge(u,v);
                addedge(v,u);
            }
        }
        int cnt=0;
        for(int i=1;i<=n;i++)
        if (!DFN[i]){
            Tarjan(i,i);
            cnt++;
        }
        int num=0;
        for(int i=1;i<=n;i++)
            if (cut[i]) num++;
        printf("%d\n",num);
    }
    return 0;
}