CCC '18 J5 - Choose your own path

//Ivan Li, Markville secondary school
import java.io.*;
import java.util.*;


public class Main{
  public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);

    //to check if all nodes are visited
    //we can check if all nodes are NOT equal to Integer.MAX_VALUE
 


    //input int N
    //create integer linkedlist called Ending
 
    //create arraymatrix with dimensions NxN

    //use for loop to repeat N times
      //input int Nev
      //if Nev = 0 then add i into Ending
      //create nested for loop and repeat Nev times
        //input int ev
        //ev -= 1
        //store map[i][ev]=true
    int N = sc.nextInt();
    LinkedList<Integer> Ending = new LinkedList<Integer>();
    boolean map[][] = new boolean[N][N];
    for(int i =0; i<N; i++){
     int Nev = sc.nextInt();
      if(Nev==0){
        Ending.add(i);
      }
      for(int a=0; a<Nev; a++){
        int ev = sc.nextInt();
        ev-=1;
        map[i][ev]=true;
        
      }
    }
 
 
    
    //create integer linkedlist called list
    //add 0 to list
    LinkedList<Integer> list = new LinkedList<Integer>();
    list.add(0);
    
    // create a mincost array with dimension N
    //fill mincost with Integer.MAX_VALUE
    //set mincost[0]=1
    
    int [] mincost = new int[N];
    Arrays.fill(mincost,Integer.MAX_VALUE);
    mincost[0] = 1;

    // create while loop with condition !list.isEmpty()
    //create int next with value list.poll()
    //use a for loop to check every neighbour of next
        //if mincost[next]+1<mincost[i]
        //add i into list
        //set cost of i to be mincost[next]+1
    
    while (!list.isEmpty()){
      
      int next = list.poll();
      
      for(int i=0; i<N; i++){
        if(mincost[next]+1 < mincost[i] && map[next][i]==true){
          list.add(i);
          mincost[i] = mincost[next]+1;
        }
      }
      
    }
 


    //check every mincost for every node
      //if mincost at a certain node i equal to Integer.MAXVALUE
        //output "N"
        //return
    int min = Integer.MAX_VALUE;
    while(!Ending.isEmpty()){
      int tmp = Ending.poll();
      if(mincost[tmp]<min){
        min = mincost[tmp];
      }
    }
    for (int i : mincost) {
      if (i == Integer.MAX_VALUE){
        System.out.println("N");
        System.out.println(min);
        return;
      }
    }
          
          
    // find minimum cost between all ending nodes using Ending list
    //output "Y"
    //minimum
    
    
    System.out.println("Y");
    System.out.println(min);




  }
}