自己写的。主要时排序。

import java.util.*;


public class Main {
    public static boolean isBroather(String str1, String str2) {
        char[] arr1 = str1.toCharArray();
        char[] arr2 = str2.toCharArray();
        Arrays.sort(arr1);
        Arrays.sort(arr2);
        for (int i = 0; i < arr1.length; i++) {
            if (arr1[i] != arr2[i]) {
                return false;
            }
        }
        return true;
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNextLine()) {
            String[] in = sc.nextLine().split(" ");
            int n = in.length;
            String x = in[n - 2];
            int k = Integer.valueOf(in[n - 1]);
            List<String> broathers = new ArrayList<>();    //存储兄弟单词
            for (int i = 1; i < n - 2; i++) {
                if (in[i].length() == x.length() && x.compareTo(in[i]) != 0 &&
                        isBroather(in[i], x)) {
                    broathers.add(in[i]);
                }
            }
            System.out.println(broathers.size());
            Collections.sort(broathers);  //排序
            if (k <= broathers.size()) {
                int i = 1;
                for (String s : broathers) {
                    if (i == k) {
                        System.out.println(s);
                    }
                    i++;
                }
            }
        }
    }
}