[20250923] BOJ / G5 / 회장뽑기 / 김민진

zinnnn37/202509/23 BOJ G5 회장뽑기.md

@@ -0,0 +1,92 @@
+```java
+import java.io.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.StringTokenizer;
+
+public class BJ_2660_회장뽑기 {
+
+	private static final int INF = 987654321;
+
+	private static final BufferedReader  br = new BufferedReader(new InputStreamReader(System.in));
+	private static final BufferedWriter  bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	private static final StringBuilder   sb = new StringBuilder();
+	private static       StringTokenizer st;
+
+	private static int           N;
+	private static int[][]       graph;
+	private static List<Integer> candidate;
+
+	public static void main(String[] args) throws IOException {
+		init();
+		sol();
+	}
+
+	private static void init() throws IOException {
+		N = Integer.parseInt(br.readLine());
+
+		graph = new int[N + 1][N + 1];
+		for (int i = 1; i <= N; i++) {
+			for (int j = 1; j <= N; j++) {
+				if (i == j) continue;
+				graph[i][j] = INF;
+			}
+		}
+
+		candidate = new ArrayList<>();
+		while (true) {
+			st = new StringTokenizer(br.readLine());
+
+			int u = Integer.parseInt(st.nextToken());
+			int v = Integer.parseInt(st.nextToken());
+
+			if (u == -1 && v == -1) break;
+
+			graph[u][v] = 1;
+			graph[v][u] = 1;
+		}
+	}
+
+	private static void sol() throws IOException {
+		for (int k = 1; k <= N; k++) {
+			for (int i = 1; i <= N; i++) {
+				for (int j = 1; j <= N; j++) {
+					if (i == j || i == k || j == k) continue;
+
+					if (graph[i][j] > graph[i][k] + graph[k][j]) {
+						graph[i][j] = graph[i][k] + graph[k][j];
+					}
+				}
+			}
+		}
+
+		int tmp = INF;
+		for (int i = 1; i <= N; i++) {
+			int max = 0;
+			for (int j = 1; j <= N; j++) {
+				if (graph[i][j] == INF) continue;
+
+				max = Math.max(graph[i][j], max);
+			}
+
+			if (max == tmp) {
+				candidate.add(i);
+			} else if (max < tmp) {
+				tmp = max;
+				candidate.clear();
+				candidate.add(i);
+			}
+		}
+
+		sb.append(tmp).append(" ").append(candidate.size()).append("\n");
+		for (int i : candidate) {
+			sb.append(i).append(" ");
+		}
+		bw.write(sb.toString());
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+
+}
+```