백준 1764

package baekjoon.이분탐색;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

class Main1764 {

   static int N, M, ans;
   static String[] n, m;
   static StringBuilder sb = new StringBuilder();

   public static void main(String[] args) throws Exception {
      input();
      for (int i = 0; i < M; i++) {
         go(m[i]);
      }
      System.out.println(ans);
      System.out.println(sb);
   }

   private static void go(String s) {
      int L = 0;
      int R = N - 1;
      while (L <= R) {
         int mid = (L + R) / 2;
         if (n[mid].compareTo(s) < 0) {
            L = mid + 1;
         } else if (n[mid].compareTo(s) > 0) {
            R = mid - 1;
         } else if (n[mid].equals(s)) {
            sb.append(s).append('\n');
            ans++;
            break;
         }
      }
   }

   private static void input() throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      N = Integer.parseInt(st.nextToken());
      M = Integer.parseInt(st.nextToken());
      n = new String[N];
      m = new String[M];
      for (int i = 0; i < N; i++) {
         n[i] = br.readLine();
      }
      for (int i = 0; i < M; i++) {
         m[i] = br.readLine();
      }
      Arrays.sort(n);
      Arrays.sort(m);
   }
}