POJ 1655 - Balancing Act 树型DP

     这题和POJ 3107 - Godfather异曲同工...http://blog.csdn.net/kk303/article/details/9387251

 

Program:

 

#include<iostream>

#include<stdio.h>

#include<string.h>

#include<set>

#include<ctime>

#include<algorithm>

#include<queue>

#include<cmath>

#include<map>

#define oo 1000000007

#define ll long long

#define pi acos(-1.0)

#define MAXN 20005

using namespace std;

struct node

{

      int x,y,next;

}line[MAXN*2];

int _next[MAXN],n,AnsData,AnsNote;

bool used[MAXN];

void addline(int x,int y,int m)

{

      line[m].next=_next[x],_next[x]=m;

      line[m].x=x,line[m].y=y;

      return;

}

int dfs(int x)

{

      int k,data=0,num=0,t;

      k=_next[x];

      while (k)

      {

            if (!used[line[k].y])

            {

                  used[line[k].y]=true;

                  t=dfs(line[k].y);

                  data=max(t,data);

                  num+=t;

                  used[line[k].y]=false;

            }

            k=line[k].next;

      }

      num++;

      data=max(data,n-num);

      if ((data<AnsData) || (data==AnsData && AnsNote>x))

         AnsNote=x,AnsData=data;

      return num;

}

int main()

{

      int T,i,num; 

      scanf("%d",&T);

      while (T--)

      {

             scanf("%d",&n);

             memset(_next,0,sizeof(_next));

             num=0;

             for (i=1;i<n;i++)

             {

                   int x,y;

                   scanf("%d%d",&x,&y);

                   addline(x,y,++num);

                   addline(y,x,++num);

             }

             memset(used,false,sizeof(used));

             used[1]=true,AnsData=oo;

             dfs(1);

             printf("%d %d\n",AnsNote,AnsData);

      }

      return 0;

}