题解 | #查找兄弟单词#

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

// 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 num = in.nextInt();
        String[] ss = new String[num];
        for (int i = 0; i < num; i++) {
            ss[i] = in.next();
        }
        String word = in.next();
        int key = in.nextInt();
        List<String> list = new ArrayList();

        for (int i = 0; i < num; i++) {
            if (isBrother(word, ss[i])) {
                list.add(ss[i]);
            }
        }
        System.out.println(list.size());
        String[] result = list.toArray(new String[list.size()]);
        Arrays.sort(result);
        for (int i = 0; i < result.length; i++) {
            if (i == key-1) {
                System.out.println(result[i]);
            }
        }
        
    }
    public static boolean isBrother(String word, String s) {
        if (word.length()!=s.length()||word.equals(s)) {
            return false;
        }
        char[] w = word.toCharArray();
        Arrays.sort(w);
        char[] ss = s.toCharArray();
        Arrays.sort(ss);
        return String.valueOf(w).equals(String.valueOf(ss));
    }
}

知识点：

List<String> list = new ArrayList();

String[] result = list.toArray(new String[list.size()]);

Arrays.sort(result);

这里不能用treeset、虽然其是有序的但是不重复。