poj2378

/***************************************************************\

 *Author:Hu Wenbiao

 *Created Time: Tue 17 Aug 2010 05:56:33 PM CST

 *File Name: main.cpp

 *Description:树状dp。跟poj1655几乎相同

\***************************************************************/

//*========================*Head File*========================*\\



#include<iostream>

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

/*----------------------*Global Variable*----------------------*/

int first[10010],N,X,Y,dp[10010],tot;

struct Edge{

 int to,next;

}edge[20010];

//*=======================*Main Program*=======================*//

using namespace std;



void insertedge(int X,int Y){

 edge[tot].to=Y;

 edge[tot].next=first[X];

 first[X]=tot++;

 edge[tot].to=X;

 edge[tot].next=first[Y];

 first[Y]=tot++;

}

int tree_dp(int from,int now){

 int sum=1,_max=0,tmp;

 int p=first[now],to;

 while(p!=-1){

  to=edge[p].to;

  p=edge[p].next;

  if(to==from)continue;

  tmp=tree_dp(now,to);

  if(_max<tmp)

    _max=tmp;

  sum+=tmp;

 }

 dp[now]=N-sum>_max?N-sum:_max;

 return sum;

}

int main(){

 //freopen("input","r",stdin);

 while(scanf("%d",&N)!=EOF){

  memset(first,-1,sizeof(first));

  tot=0;

  for(int i=1;i<N;i++){

   scanf("%d%d",&X,&Y);

   insertedge(X,Y);

  }

  tree_dp(0,1);

  for(int i=1;i<=N;i++){

   if(dp[i]<=N/2)

     printf("%d\n",i);

  }

 }

}