题解 | #查找兄弟单词#

import java.util.*;
import java.util.regex.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            int n = in.nextInt();
            String[] strs = new String[n];
            for(int i=0;i<n;i++) 
                strs[i]=in.next();
            Arrays.sort(strs);
            String str = in.next();
            int k = in.nextInt();
            int count = 0;
            List<Character> list = new ArrayList<Character>();
            List<String> resList = new ArrayList<String>();
            for(int i=0;i<str.length();i++)
                list.add(str.charAt(i));
            Collections.sort(list);
            Pattern p = Pattern.compile("[^"+str+"]");
            for(String s : strs) {
                List<Character> list2 = new ArrayList<Character>();
                for(int i=0;i<s.length();i++)
                    list2.add(s.charAt(i));
                Collections.sort(list2);                
                boolean isEqual = list.equals(list2);
                if(!p.matcher(s).find() && !s.equals(str) && s.length()==str.length() && isEqual) {
                    count++;
                    resList.add(s);
                }
            }
            System.out.println(count);
            if(k<=resList.size())
                System.out.println(resList.toArray()[k-1]);
        }
    }
}