94 lines
2.1 KiB
C++
94 lines
2.1 KiB
C++
#include<iostream>
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#include<cstdio>
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#include<cstring>
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#include<algorithm>
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using namespace std;
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#define MAXN 111111
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#pragma comment(linker,"/STACk:10240000,10240000")
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struct Edge{
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int v,next;
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}edge[MAXN*4];
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int n,m,cnt,NE,BridgeNum;
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int head[MAXN];
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int parent[MAXN];
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int isbridge[MAXN];
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int low[MAXN],dfn[MAXN];
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bool mark[MAXN];
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void Insert(int u,int v)
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{
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edge[NE].v=v;
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edge[NE].next=head[u];
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head[u]=NE++;
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}
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void Tarjan(int u,int father)
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{
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int flag=0;
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low[u]=dfn[u]=++cnt;
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mark[u]=true;
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for(int i=head[u];i!=-1;i=edge[i].next){
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int v=edge[i].v;
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if(v==father&&!flag){ flag=1;continue; }
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if(dfn[v]==0){
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parent[v]=u;
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Tarjan(v,u);
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low[u]=min(low[u],low[v]);
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if(low[v]>dfn[u]){
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isbridge[v]=1;
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BridgeNum++;
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}
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}else if(mark[v]){
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low[u]=min(low[u],dfn[v]);
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}
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}
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}
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void LCA(int u,int v)
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{
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while(dfn[u]>dfn[v]){
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if(isbridge[u]){
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BridgeNum--;
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isbridge[u]=0;
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}
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u=parent[u];
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}
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while(dfn[v]>dfn[u]){
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if(isbridge[v]){
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BridgeNum--;
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isbridge[v]=0;
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}
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v=parent[v];
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}
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while(u!=v){
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if(isbridge[u]){ BridgeNum--;isbridge[u]=0; }
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if(isbridge[v]){ BridgeNum--;isbridge[v]=0; }
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u=parent[u],v=parent[v];
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}
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}
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int main()
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{
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int u,v,Q,_case=1;
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while(~scanf("%d%d",&n,&m)){
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if(n==0&&m==0)break;
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BridgeNum=NE=cnt=0;
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memset(head,-1,sizeof(head));
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while(m--){
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scanf("%d%d",&u,&v);
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Insert(u,v);
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Insert(v,u);
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}
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memset(isbridge,0,sizeof(isbridge));
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memset(dfn,0,sizeof(dfn));
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memset(mark,false,sizeof(mark));
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for(int i=1;i<=n+1;i++)parent[i]=i;
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Tarjan(1,-1);
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printf("Case %d:\n",_case++);
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scanf("%d",&Q);
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while(Q--){
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scanf("%d%d",&u,&v);
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LCA(u,v);
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printf("%d\n",BridgeNum);
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}
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printf("\n");
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}
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return 0;
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}
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