题解 | #查找兄弟单词#

import java.util.*;

// 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);
        int n=in.nextInt();
        String[] arr=new String[n];
        ArrayList<String> list=new ArrayList<String>();
        for(int i=0;i<n;i++){
            arr[i]=in.next();
        }
        String str=in.next();
        int k=in.nextInt();
        int res=0;
        for(int i=0;i<n;i++){
            if(isBrother(str,arr[i])){
                res++;
                list.add(arr[i]);
            }
        }
        Collections.sort(list);
        System.out.println(list.size());
        if(k<=list.size()){
            System.out.println(list.get(k-1));
        }
    }
    public static boolean isBrother(String s1,String s2){
        if(s1.length()!=s2.length())return false;
        if(s1.equals(s2))return false;
        int len=s1.length();
        HashMap<Character,Integer> m1=new  HashMap<Character,Integer>();
        HashMap<Character,Integer> m2=new  HashMap<Character,Integer>();
        for(int i=0;i<len;i++){
            char c1=s1.charAt(i);
            char c2=s2.charAt(i);            
            m1.put(c1,m1.getOrDefault(c1,0)+1);
            m2.put(c2,m2.getOrDefault(c2,0)+1);
        }
        // System.out.println(m1.toString());
        if(m1.size()!=m2.size())return false;
        for(char c:m1.keySet()){
            if(m1.get(c)!=m2.get(c))return false;
        }
        return true;
    }
}