Poj Solution 1909

http://poj.org/problem?id=1909

//* @author: ccQ.SuperSupper
import java.util.*;
import java.io.*;
class node{
    int init_have;
    int sum_have;
    int nodes;
    Vector son = new Vector();
}
public class Main {
    
 static int N = 10000+100;
 public static void main(String []args) throws Exception{
        
  int n,i,j,ans,cnt,sons,root;
  node Tree[] = new node[N];
  for(i=0;i< N;++i) Tree[i] = new node();
        
   //Scanner cin = new Scanner(new FileInputStream("input.txt"));//System.in);
   Scanner cin = new Scanner(System.in);
        
   while(cin.hasNext()){
    n = cin.nextInt();
    if(n==0) break;
    for(i=0;i<=n;++i){
        Tree[i].sum_have = -1;
        Tree[i].son.clear();
        Tree[i].nodes = 0;
    }
    for(i=0;i< n;++i){
        cnt = cin.nextInt();
        Tree[cnt].init_have = cin.nextInt();
        sons = cin.nextInt();
        for(j=0;j< sons;++j){
            ans = cin.nextInt();
            Tree[cnt].son.add(ans);
            Tree[ans].sum_have = -2;
        }
    }
    root = 1;
    for(i=1;i<=n;++i) if(Tree[i].sum_have==-1)
        root = i;
    System.out.println(dfs(Tree,root));
   }
 }

public static int dfs(node Tree[],int root){
    
  int i,j,k,ans=0;
  Tree[root].sum_have = Tree[root].init_have;
  Tree[root].nodes = 1;
  for(i=0;i< Tree[root].son.size();++i){
    k = (Integer)Tree[root].son.get(i);
    if(Tree[k].sum_have< 0){
        ans+=dfs(Tree,k);
        Tree[root].sum_have+=Tree[k].sum_have;
        Tree[root].nodes+=Tree[k].nodes;
        ans+=abs(Tree[k].sum_have-Tree[k].nodes);
    }
   }
   return ans;
 }
    public static int abs(int a){
        return a<0?-a:a;
    }
}