POJ 3107

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#define MAXN 50010
using namespace std;
typedef struct PP{
    int id,par;
    bool operator < (const PP & a) const{
        if(par == a.par) return id < a.id;
        return par < a.par;
    }
}Partition;
typedef struct{
    int to,next;
}Node;
Node edge[2*MAXN];
Partition P[MAXN];
int head[MAXN],vis[MAXN],cnt[MAXN],N;
void addedge(int u,int v,int k){
    edge[k].to = v;
    edge[k].next = head[u];
    head[u] = k;
}
int dfs_child(int s){
    vis[s] = cnt[s] = 1;
    for(int i = head[s];~i;i = edge[i].next){
        int u = edge[i].to;
        if(!vis[u]) cnt[s] += dfs_child(u);
    }
    return cnt[s]--;
}
void dfs_partition(int s){
    P[s].id = s;
    P[s].par = N-cnt[s]-1;
    vis[s] = 1;
    for(int i = head[s];~i;i = edge[i].next){
        int u = edge[i].to;
        if(!vis[u]){
            P[s].par = max(P[s].par,cnt[u]+1);
            dfs_partition(u);
        }
    }
}
int main(){
    int u,v;
    while(~scanf("%d",&N)){
        int k = 1;
        memset(head,-1,sizeof(head));
        for(int i = 1;i <= N-1;i ++){
            scanf("%d%d",&u,&v);
            addedge(u,v,k++);
            addedge(v,u,k++);
        }
        memset(vis,0,sizeof(vis));
        dfs_child(1);
        memset(vis,0,sizeof(vis));
        dfs_partition(1);
        sort(P+1,P+N+1);
        k = 1;
        while(P[k].par == P[1].par){
            printf("%d ",P[k].id);
            k++;
        }
        printf("
");
    }
    return 0;
}