HDU 3078 Network

简单的  RMQ；  先预处理得到  所有 节点的 公共祖先  和  dfs 得到所有节点的父亲节点；  然后  询问时，从自己出发向上找父亲， 然后  得到所有的节点；排序一下

不知道  这题这样也能过；为什么不会超时啊？？？？？？？？？？？；

 #include<iostream>
 #include<cstring>
 #include<algorithm>
 #include<cmath>
 #include<stdio.h>
 #include<vector>
 using namespace std;
 const int maxn = ;
 struct date{
    int v,next;
 }edge[maxn<<]; int total,head[maxn];
 int N,Q,node[maxn],fath[maxn];
 void add_edge( int u,int v ){
     edge[total].v = v;
     edge[total].next = head[u];
     head[u] = total++;
 }
 bool vis[maxn]; int dep[maxn<<],sta[maxn<<],tab[maxn<<],dp[maxn<<][],num;
 void dfs1( int son,int fa ){
     vis[son] = true; fath[son] = fa;
     for( int i = head[son]; i != -; i = edge[i].next ){
         int v = edge[i].v;
         if( !vis[v] )dfs1( v,son );
     }
 }
 void LCA( int son,int deep ){
     dep[num] = deep; sta[son] = num; tab[num] = son;   num++; vis[son] = true;
     for( int i = head[son]; i != -; i = edge[i].next ){
         int v = edge[i].v;
         if( !vis[v] ){ LCA( v,deep+ ); dep[num] = deep; tab[num] = son; num++; }
     }
 }
 int work( int n1,int n2 ){
    if( dep[n1] < dep[n2] )return n1;
    return n2;
 }
 void RMQ( ){
     for( int i = ; i <= num; i++ )dp[i][] = i;
     for( int i = ; (<<i) <= num; i++ ){
         for( int j = ; j -  + (<<i) <= num; j++ )
         dp[j][i] = work( dp[j][i-], dp[j+(<<(i-))][i-] );
     }
 }
 int query( int L,int R ){
     int k = ;
     while( (<<(k+)) <= R-L+ )k++;
     return tab[work( dp[L][k],dp[R-(<<k)+][k] )];
 }
 vector<int>vv;
 bool cmp( int a,int b ){
    return a > b;
 }
 void DO( int u,int v,int fa,int k ){
     vv.clear();
     while( u != fa ){
        vv.push_back( node[u] );
        u = fath[u];
     }
     while( v != fa  ){
        vv.push_back( node[v] );
        v = fath[v];
     }
     vv.push_back( node[fa] ); sort( vv.begin(),vv.end(),cmp );
     //for( int i = 0; i < vv.size(); i++ )cout<<vv[i]<<endl;
     if( vv.size() < k )puts("invalid request!");
     else printf("%d\n",vv[k-]);
 }
 int main(){
       while( scanf("%d%d",&N,&Q) != EOF ){
           memset( head,-,sizeof(head) ); total = ;
           for( int i = ; i <= N; i++ )fath[i] = i;
           for( int i = ; i <= N; i++ )scanf("%d",&node[i]);
           for( int i = ; i <  N; i++ )
           {
               int u,v; scanf("%d%d",&u,&v);
               add_edge( u,v );
               add_edge( v,u );
           }
           memset( vis,,sizeof(vis) );
           dfs1( ,- ); fath[] = ;
           memset( vis,,sizeof(vis) );num = ;
           LCA( , );
           //for( int i = 1; i < num; i++ )
           //cout<<i<<" "<<dep[i]<<" "<<tab[i]<<endl;
           num--;  RMQ( );
           while( Q-- ){
                int k,u,v; scanf("%d%d%d",&k,&u,&v);
                if( k ==  ){ node[u] = v; continue; }
                //cout<<node[4]<<endl;
                if( sta[u] > sta[v] )swap( u,v );
                //cout<<query( sta[u],sta[v] )<<endl;
                DO( u,v,query( sta[u],sta[v] ),k );
           }
       }
       return ;
 }
 /*

 7 100
 5 1 4 2 4 3 6
 1 2
 1 3
 1 4
 2 5
 3 6
 4 7

 */