[20251119] PGM / Lv3 / 가장 먼 노드 / 이강현

lkhyun/202511/19 PGM Lv3 가장 먼 노드.md

@@ -0,0 +1,48 @@
+```java
+import java.util.*;
+class Solution {
+    static int answer = 0;
+    static int max = 0;
+    static List<Integer>[] adjList;
+    public int solution(int n, int[][] edge) {
+        answer = 0;
+        adjList = new List[n+1];
+        for(int i = 0; i<=n; i++){
+            adjList[i] = new ArrayList<>();
+        }
+
+        for(int[] e : edge){
+            int a = e[0];
+            int b = e[1];
+            adjList[a].add(b);
+            adjList[b].add(a);
+        }
+
+        BFS(n);
+
+        return answer;
+    }
+    public static void BFS(int n){
+        ArrayDeque<int[]> q = new ArrayDeque<>();
+        boolean[] visited = new boolean[n+1];
+        q.offer(new int[]{1,0});
+        visited[1] = true;
+
+        while(!q.isEmpty()){
+            int[] cur = q.poll();
+            if(max < cur[1]){
+                max = cur[1];
+                answer = 1;
+            }else if(max == cur[1]){
+                answer++;
+            }
+            for(int next : adjList[cur[0]]){
+                if(!visited[next]){
+                    q.offer(new int[]{next,cur[1]+1});
+                    visited[next] = true;
+                }
+            }
+        }
+    }
+}
+```