POJ 1470 Closest Common Ancestors

裸的求LCA的题，今天看看了下，写下增加点认识。。。

有关tarjan的LCA的：

http://hi.baidu.com/niuniu_2006923/blog/item/3d57d0235ce7ae5a9922ed68.html

http://blog.csdn.net/apachecq/archive/2009/01/11/3753364.aspx

 

代码：

#include<iostream>#include<cstdio>#include<memory.h>#include<queue>using namespace std;const int MAX=905;struct node{int v,next;}g[MAX*MAX],query[MAX*MAX];int parent[MAX],ancestor[MAX],cnt[MAX],adj[MAX],adj2[MAX],ind[MAX];bool check[MAX];int e,n,m,e2;int find(int x){if(x!=parent[x])parent[x]=find(parent[x]);return parent[x];}void lca(int u){int i,v;parent[u]=u;ancestor[find(u)]=u;for(i=adj[u];i!=-1;i=g[i].next){v=g[i].v;//cout<<v<<" "<<g[i].next<<endl;lca(v);parent[v]=u;ancestor[find(u)]=u;}check[u]=true;for(i=adj2[u];i!=-1;i=query[i].next){v=query[i].v;//cout<<v<<endl;if(check[v])cnt[ancestor[find(v)]]++;}}int main(){int i,j,k,a;while(scanf("%d",&n)!=EOF){e=0;memset(cnt,0,sizeof(cnt));memset(adj,-1,sizeof(adj));memset(ind,0,sizeof(ind));memset(check,false,sizeof(check));for(i=1;i<=n;i++)parent[i]=i;for(a=1;a<=n;a++){scanf(" %d:(%d)",&i,&k);//cout<<j<<" "<<k<<endl;while(k--){scanf("%d",&j);g[e].v=j;g[e].next=adj[i];adj[i]=e++;ind[j]++;}}scanf("%d",&m);e2=0;memset(adj2,-1,sizeof(adj2));while(m--){scanf(" (%d%d)",&i,&j);//cout<<i<<" "<<j<<endl;query[e2].v=j;query[e2].next=adj2[i];adj2[i]=e2++;query[e2].v=i;query[e2].next=adj2[j];adj2[j]=e2++;}//cout<<"yes"<<endl;for(i=1;i<=n;i++)if(ind[i]==0)//找树根 break;lca(i);for(i=1;i<=n;i++){if(cnt[i]>0)printf("%d:%d/n",i,cnt[i]);}}return 0;}