프로그래머스 : 가장먼노드

import java.util.*;
class Solution {
    static List<Integer>[] Edge;
    public int solution(int n, int[][] edge) {
        Edge = new ArrayList[n+1];
        for(int i=1;i<=n;i++){
            Edge[i] = new ArrayList<Integer>();
        }
        
        for(int i=0; i< edge.length; i++){
            int u = edge[i][0];
            int v = edge[i][1];
            
            Edge[u].add(v);
            Edge[v].add(u);
        }
        
        Queue<Integer> q = new LinkedList<Integer>();
        q.add(1);
        check = new boolean[n+1];
        check[1] = true;
           
        int time = 0;
        int answer = 0;
        while(!q.isEmpty()){
            int size = q.size();
            int tmp = 0;
            for(int s=0;s<size;s++){
                int cur = q.poll();
                
                for(int next : Edge[cur]){
                    if(check[next])
                        continue;
                    check[next] = true;
                    tmp++;
                    q.add(next);
                }
            }
            if(tmp!=0)
                answer = tmp;
            
            ++time;
          
            
        }

        return answer;
    }
    static boolean check[];
    static int answer =0;
}