1253 SPF//

//求割点 #include<cstdio> #define min(a,b) a>b?b:a; #define max(a,b) a>b?a:b; const int V=1001; struct Edge { int next,adj; } edge[V*V]; int cnt,idx; int cut[V],n,head[V]; int low[V],dfn[V]; void init() { cnt=0; idx=0; for(int i=1; i<=V; i++) { head[i]=-1; low[i]=0; dfn[i]=0; cut[i]=0; } } void addedge(int u,int v) { edge[cnt].adj=v; edge[cnt].next=head[u]; head[u]=cnt++; } void tarjan(int u,int fa) { low[u]=dfn[u]=(++idx); //printf("u=%d/n",u); for(int p=head[u]; p!=-1; p=edge[p].next) { int v=edge[p].adj; if(v==fa) continue; if(dfn[v]!=0) { low[u]=min(dfn[v],low[u]); continue; } tarjan(v,u); low[u]=min(low[u],low[v]); if(low[v]>=dfn[u]) cut[u]++;//访问不到比U小的节点 } if(fa!=0) cut[u]++; } int main() { int a,b; int num=0; while(scanf("%d",&a)!=EOF) { if(a==0) break; init(); n=0; scanf("%d",&b); n=max(a,n); n=max(b,n); addedge(a,b); addedge(b,a); if(num>0) printf("/n"); printf("Network #%d/n",++num); while(1) { scanf("%d",&a); if(a==0) break; scanf("%d",&b); n=max(a,n); n=max(b,n); addedge(a,b); addedge(b,a); } tarjan(1,0); bool flag=false; for(int i=1; i<=n; i++) if(cut[i]>1) { printf(" SPF node %d leaves %d subnets/n",i,cut[i]); flag=true; } if(!flag) printf(" No SPF nodes/n"); } return 0; }