Aizu Online Judge 0144 Packet Transportation

■0144 Packet Transportation

BFSするだけ．

import java.util.*;
import java.lang.*;
import java.math.*;
import java.io.*;

import static java.lang.Math.*;
import static java.util.Arrays.*;

public class Main{

 Scanner sc=new Scanner(System.in);

 int INF=1<<28;
 double EPS=1e-9;

 int n;
 int start, goal, ttl;
 LinkedList<Integer>[] graph;

 @SuppressWarnings("unchecked")
 void run(){
  n=sc.nextInt();
  graph=new LinkedList[n];
  for(int j=0; j<n; j++){
   int u=sc.nextInt()-1;// ルータ番号
   int m=sc.nextInt();
   graph[u]=new LinkedList<Integer>();
   for(int i=0; i<m; i++){
    int v=sc.nextInt()-1;
    graph[u].add(v);
   }
  }
  int p=sc.nextInt();
  for(int i=0; i<p; i++){
   start=sc.nextInt()-1;
   goal=sc.nextInt()-1;
   ttl=sc.nextInt();
   solve();
  }
 }

 void solve(){
  LinkedList<Integer> que=new LinkedList<Integer>();
  boolean[] visited=new boolean[n];
  int[] d=new int[n];
  Arrays.fill(d, INF);
  que.offer(start);
  d[start]=1;
  visited[start]=true;
  for(; !que.isEmpty();){
   int u=que.poll();
   for(int v : graph[u]){
    if(!visited[v]){
     que.offer(v);
     d[v]=d[u]+1;
     visited[v]=true;
    }
   }
  }
  if(d[goal]<=ttl){
   println(""+d[goal]);
  }else{
   println("NA");
  }
 }

 void debug(Object... os){
  System.err.println(Arrays.deepToString(os));
 }

 void print(String s){
  System.out.print(s);
 }

 void println(String s){
  System.out.println(s);
 }

 public static void main(String[] args){
  // System.setOut(new PrintStream(new BufferedOutputStream(System.out)));
  new Main().run();
 }
}