delete pics to save space

3.34108.cpp

@@ -0,0 +1,84 @@
+#include<cstdio>
+#include<stack>
+#include<vector>
+#include<algorithm>
+using namespace std;
+template<typename T> inline void read(T& t)
+{
+    t=0; bool f=false; char ch;
+    while(ch=getchar(),!((ch>='0'&&ch<='9')||ch=='-'));
+    if(ch=='-') f=true,ch=getchar();
+    t=ch-'0';
+    while(ch=getchar(),ch>='0'&&ch<='9') t=t*10+ch-'0';
+    if(f) t=-t;
+}
+template<typename T,typename... Args> inline void read(T& t,Args&... args) { read(t); read(args...); }
+inline void write(int v)
+{
+	int stk[10],top;
+	while(v>0) stk[top++]=v%10,v/=10;
+	while(top>0) putchar(stk[--top]+'0');
+	putchar(' ');
+}
+const int maxn=1e6+5;
+struct Edge { int u,v; };
+int pre[maxn],bccno[maxn],dfs_clock,bcc_cnt; bool iscut[maxn];
+vector<int> G[maxn],bcc[maxn];
+stack<Edge> stk;
+int dfs(int u,int fa)
+{
+	int lowu=pre[u]=++dfs_clock,child=0;
+	for(int i=0;i<G[u].size();i++)
+	{
+		int v=G[u][i];
+		Edge e=(Edge){u,v};
+		if(!pre[v])
+		{
+			stk.push(e);
+			child++;
+			int lowv=dfs(v,u);
+			lowu=min(lowu,lowv);
+			if(lowv>=pre[u])
+			{
+				iscut[u]=true; bcc_cnt++;
+				while(true)
+				{
+					Edge x=stk.top(); stk.pop();
+					if(bccno[x.u]!=bcc_cnt) { bcc[bcc_cnt].push_back(x.u); bccno[x.u]=bcc_cnt; }
+					if(bccno[x.v]!=bcc_cnt) { bcc[bcc_cnt].push_back(x.v); bccno[x.v]=bcc_cnt; }
+					if(x.u==u&&x.v==v) break;
+				}
+			}
+		}
+		else if(pre[v]<pre[u]&&v!=fa)
+		{
+			stk.push(e);
+			lowu=min(lowu,pre[v]);
+		}
+	}
+	if(fa<0&&child<=1) iscut[u]=false;
+	return lowu;
+}
+int n,m,a,b; 
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+	freopen("pro.out","w",stdout);
+#endif
+	read(n,m);
+	while(m-->0)
+	{
+		read(a,b);
+		G[a].push_back(b); G[b].push_back(a);
+	}
+	for(int i=1;i<=n;i++) if(!pre[i]) dfs(i,-1);
+	printf("%d\n",bcc_cnt);
+	for(int i=1;i<=bcc_cnt;i++)
+	{
+		printf("%d ",bcc[i].size());
+		for(int j=0;j<bcc[i].size();j++) write(bcc[i][j]);
+		putchar('\n');
+	}
+	return 0;
+}