Вроде работает но валидатору не понравился моё решения
package com.javarush.task.task18.task1825;
import java.io.*;
import java.util.*;
/*
Собираем файл
*/
public class Solution {
public static void main(String[] args) throws Exception{
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String fileName = "";
ArrayList<String> list = new ArrayList<>();
Map<Integer, String> tree = new TreeMap<>();
while (!(fileName = reader.readLine()).equals("end")){
list.add(fileName);
}
for(String s : list){
int index = Integer.parseInt(s.substring(s.indexOf(".part") + 5));
tree.put(index, s);
}
FileOutputStream out = new FileOutputStream("C:/folder/Lion.avi", true);
for(Map.Entry t : tree.entrySet()){
FileInputStream in = new FileInputStream(String.valueOf(t.getValue()));
BufferedInputStream bufferedInputStream = new BufferedInputStream(in);
int i;
while((i = bufferedInputStream.read())!= -1){
out.write(i);
}
in.close();
bufferedInputStream.close();
}
out.close();
}
}
/*
C:/folder/Lion.avi.part5
C:/folder/Lion.avi.part3
C:/folder/Lion.avi.part7
C:/folder/Lion.avi.part4
C:/folder/Lion.avi.part1
C:/folder/Lion.avi.part10
C:/folder/Lion.avi.part2
C:/folder/Lion.avi.part6
C:/folder/Lion.avi.part8
C:/folder/Lion.avi.part9
end
*/