Пробовал на разных примерах. Вроде работает как надо, но валидатору что-то не нравится.
package com.javarush.task.task19.task1916;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
/*
Отслеживаем изменения
*/
public class Solution {
public static List<LineItem> lines = new ArrayList<LineItem>();
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String fileName1=reader.readLine();
String fileName2=reader.readLine();
FileReader file1 = new FileReader(fileName1);
FileReader file2 = new FileReader(fileName2);
BufferedReader fileReader1, fileReader2;
/*
BufferedWriter bufferedWriter1 = new BufferedWriter(new FileWriter(fileName1));
BufferedWriter bufferedWriter2 = new BufferedWriter(new FileWriter(fileName2));
bufferedWriter1.write("строка1");bufferedWriter1.newLine();
bufferedWriter1.write("строка2");bufferedWriter1.newLine();
bufferedWriter1.write("строка3");bufferedWriter1.newLine();
bufferedWriter1.write("строка4");bufferedWriter1.newLine();
bufferedWriter1.write("строка5");bufferedWriter1.newLine();
bufferedWriter1.write("строка1");bufferedWriter1.newLine();
bufferedWriter1.write("строка2");bufferedWriter1.newLine();
bufferedWriter1.write("строка3");bufferedWriter1.newLine();
bufferedWriter1.write("строка5");bufferedWriter1.newLine();
bufferedWriter1.write("строка0");
bufferedWriter2.write("строка1");bufferedWriter2.newLine();
bufferedWriter2.write("строка3");bufferedWriter2.newLine();
bufferedWriter2.write("строка5");bufferedWriter2.newLine();
bufferedWriter2.write("строка0");bufferedWriter2.newLine();
bufferedWriter2.write("строка1");bufferedWriter2.newLine();
bufferedWriter2.write("строка3");bufferedWriter2.newLine();
bufferedWriter2.write("строка4");bufferedWriter2.newLine();
bufferedWriter2.write("строка5");
bufferedWriter1.close();
bufferedWriter2.close();
*/
fileReader1 = new BufferedReader(file1);
fileReader2 = new BufferedReader(file2);
ArrayList<String> file1List = new ArrayList<>();
ArrayList<String> file2List = new ArrayList<>();
int shift1=0, shift2=0;
String s;
while ((s = fileReader1.readLine())!=null){
file1List.add(s);
//System.out.println(file1List.get(file1List.indexOf(s)));
}
//System.out.println("************");
while ((s = fileReader2.readLine())!=null){
file2List.add(s);
//System.out.println(file2List.get(file2List.indexOf(s)));
}
if(file1List.size()>file2List.size()){
for (int i = 0; i < file1List.size()-shift1; i++) {
//System.out.println(i+" "+(i+shift1)+" "+file1List.size()+" "+file2List.size());
//System.out.println(file1List.get(i+shift1)+" - "+file2List.get(i)+" : "+file2List.get(i+1));
if((i)<file2List.size()&&file1List.get(i+shift1).equals(file2List.get(i))) {
lines.add(new LineItem(Type.SAME, file1List.get(i + shift1)));
//System.out.println(Type.SAME+" "+file1List.get(i + shift1));
}
else if(i+shift1+1<file1List.size() && (i)<=file2List.size()&&file1List.get(i+shift1+1).equals(file2List.get(i))) {
lines.add(new LineItem(Type.REMOVED, file1List.get(i + shift1)));
//System.out.println(Type.REMOVED+" "+file1List.get(i + shift1));
shift1++;i--;
}
else if((i+1)<file2List.size()&&file1List.get(i+shift1).equals(file2List.get(i+1))) {
lines.add(new LineItem(Type.ADDED, file2List.get(i)));
//System.out.println(Type.ADDED+" "+file2List.get(i));
shift1--;
}
else if((i+shift1)>=file2List.size()){
lines.add(new LineItem(Type.REMOVED, file1List.get(i + shift1)));
//System.out.println(Type.REMOVED+" "+file1List.get(i+shift1));
}
}
} else{
for (int i = 0; i < file2List.size()-shift2; i++) {
//System.out.println(i+" "+(i+shift2)+" "+file2List.size());
//System.out.println(file2List.get(i+shift2)+" - "+file1List.get(i));
if((i)<file1List.size()&&file2List.get(i+shift2).equals(file1List.get(i)))
lines.add(new LineItem(Type.SAME, file2List.get(i+shift2)));
else if(i+shift2+1<file2List.size() && (i)<=file1List.size()&&file2List.get(i+shift2+1).equals(file1List.get(i))) {
lines.add(new LineItem(Type.ADDED, file2List.get(i + shift2)));
shift2++;i--;
}
else if((i+1)<file1List.size()&&file2List.get(i+shift2).equals(file1List.get(i+1))) {
lines.add(new LineItem(Type.REMOVED, file1List.get(i)));
shift2--;
}
else if((i)>=file1List.size()){
lines.add(new LineItem(Type.ADDED, file2List.get(i + shift2)));
}
}
}
/*
for (LineItem i: lines) {
System.out.println(i.type+" "+i.line);
}
*/
reader.close();
file1.close();
file2.close();
}
public static enum Type {
ADDED, //добавлена новая строка
REMOVED, //удалена строка
SAME //без изменений
}
public static class LineItem {
public Type type;
public String line;
public LineItem(Type type, String line) {
this.type = type;
this.line = line;
}
}
}