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Question about the task

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As far as I can tell, my code functions exactly as it should, but I'm still not getting the validation. Help me Guadalupe, you're my only hope!

Read 2 file names from the console: file1 and file2.
Both files contain text, but file2 is an updated version of file1. Some of the lines are still the same.
You need to create a merged version of the lines by writing them to the lines list.
The ADDED and REMOVED labels can't be used consecutively—they must always separated by the SAME label.
The example includes empty lines for clarity.
Neither the original file nor the updated file have empty lines!

Example 1:
original updated merged file1: file2: Result: (lines) line1 line1 SAME line1 line2 REMOVED line2 line3 line3 SAME line3 line4 REMOVED line4 line5 line5 SAME line5 line0 ADDED line0 line1 line1 SAME line1 line2 REMOVED line2 line3 line3 SAME line3 line4 ADDED line4 line5 line5 SAME line5 line0 REMOVED line0

Example 2:
original updated merged file1: file2: Result: (lines) line1 line1 SAME line1 line0 ADDED line0

In the example, empty lines mean that the line is not in the specified file.

Requirements:

The Solution class must contain a LineItem class.
The Solution class must have an enum called Type.
The Solution class must have a public static List<LineItem> field called lines that is initialized immediately.
In the main(String[] args) method, the program must read file names from the console (use BufferedReader).
In the main(String[] args) method, the BufferedReader used for reading input from the console must be closed after use.
The program must read the contents of the first and second file (use FileReader).
The file input streams (FileReader) must be closed.
The lines list should contain the merged version of the lines from the files. Each line should start with the label ADDED, REMOVED, or SAME, depending on the action taken.

package com.codegym.task.task19.task1916; import java.io.*; import java.util.ArrayList; import java.util.List; /* Tracking changes */ public class Solution { public static List<LineItem> lines = new ArrayList<>(); public static List<String> addedLines = new ArrayList<>(); public static void main(String[] args) throws IOException { BufferedReader console = new BufferedReader(new InputStreamReader(System.in)); ArrayList<String> original = getFileLines(console.readLine()); ArrayList<String> updated = getFileLines(console.readLine()); console.close(); populateList(original, updated); if (args.length > 0 && args[0].equals("debug")){ for (LineItem lineItem : lines){ System.out.println(lineItem.line); } } } //Reads lines from a file and returns them in list form private static ArrayList<String> getFileLines(String fileName) throws IOException { BufferedReader reader = new BufferedReader(new FileReader(fileName)); ArrayList<String> list = new ArrayList<>(); String line; while ((line = reader.readLine()) != null){ list.add(line); } reader.close(); return list; } //Goes through each list sequentially and adds them to the final list private static void populateList(List<String> original, List<String> updated){ int sameCount = 0; for (String line : original){ if (updated.contains(line)) sameCount++; } boolean sameLine = ((original.size() - sameCount) < sameCount); //sameLine determines if there are more same lines or different lines, and sets the starting point accordingly //As each line is added, the boolean is toggled, preventing repeating types while (!allLinesProcessed(original, updated)) { //loops indefinitely until all lines from the input files have been processed if (sameLine) { for (int i = 0; i < original.size() ; i++){ if (updated.contains(original.get(i)) && (!addedLines.contains(original.get(i)))){ addedLines.add(original.get(i)); lines.add(new LineItem(Type.SAME, "SAME "+original.get(i))); break; } } sameLine = false; } if (!sameLine) { for (int i = 0; i < original.size() ; i++){ if (!original.contains(updated.get(i)) && (!addedLines.contains(updated.get(i)))) { addedLines.add(updated.get(i)); lines.add(new LineItem(Type.ADDED, "ADDED " + updated.get(i))); break; } if (!updated.contains(original.get(i)) && (!addedLines.contains(original.get(i)))){ addedLines.add(original.get(i)); lines.add(new LineItem(Type.REMOVED, "REMOVED "+original.get(i))); break; } } sameLine = true; } } } //Checks the addedLines list against the original input lists to see if all lines have been processed private static boolean allLinesProcessed(List<String> original, List<String> updated){ for (String line : original){ if (!addedLines.contains(line)) return false; } for (String line : updated){ if (!addedLines.contains(line)) return false; } return true; } public static enum Type { ADDED, // New line added REMOVED, // Line deleted SAME // No change } public static class LineItem { public Type type; public String line; public LineItem(Type type, String line) { this.type = type; this.line = line; } } }

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Juan Ma

Level 41 , Arauca, Colombia

17 March 2020, 05:29

Hi, my approach was, in a loop, trying to compare "original" and "update" lists, if they are equals (SAME) add next index in both lists (to keep on comparing). If not, trying to compare next index (line) in "original" against current index in "update", if they are equals then it means a line was REMOVED in "update" file, so add next index only in "original" list (to keep on comparing). If that neither occurs, then it means that a line was ADDED in "updates" file, so add next index only in "update" list (to keep on comparing). Finally you ought to handle with extra possible lines only in any of two files. I hope this help you.