割点模板

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #define M 100010
 5 using namespace std;
 6 struct point{
 7     int to,next;
 8 }e[M<<1];
 9 int n,m,num,cnt,root,tot;
10 int head[M],cut[M],dfn[M],low[M];
11 void add(int from,int to)
12 {
13     e[++num].next=head[from];
14     e[num].to=to;
15     head[from]=num;
16 }
17 void tarjan(int x)
18 {
19     int flag=0;
20     dfn[x]=low[x]=++cnt;
21     for(int i=head[x];i;i=e[i].next)
22     {
23         int to=e[i].to;
24         if(!dfn[to])
25         {
26             tarjan(to);
27             low[x]=min(low[x],low[to]);
28             if(dfn[x]<=low[to])//′ó?a??μ?3?·￠??2?μ?x 
29             {
30                 flag++;
31                 if(x!=root||flag>1)//2?ê??ù?úμ??òo￠×óêy′óóú1 
32                 {
33                     if(!cut[x]) tot++;
34                     cut[x]=true;
35                 }
36             }
37         }
38         else low[x]=min(low[x],dfn[to]);
39     }
40 }
41 int main()
42 {
43     scanf("%d%d",&n,&m);
44     for(int i=1;i<=m;i++)
45     {
46         int x,y; scanf("%d%d",&x,&y);
47         add(x,y); add(y,x);
48     }
49     for(int i=1;i<=n;i++)
50         if(!dfn[i])
51         {
52             root=i;
53             tarjan(i);
54         }
55     printf("%d\n",tot);
56     for(int i=1;i<=n;i++)
57         if(cut[i])
58             printf("%d ",i);
59     return 0;
60 }