CodeGym/Help with Java Tasks/Got the correct output but it does not verify.

Level 22

Dubai

16.01.2021
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Got the correct output but it does not verify.

Question about the task

Introducing tags

Java Core, Level 9, Lesson 11

Resolved

I have worked on this for hours and this is probably the best i could do .. please help.

Read from the console the name of a file containing HTML.

Example:
Info about Leela Leela Turanga
Supergirl

The main method's first parameter is a tag name. For example, "span".
Display all tags that match the specified tag.
The order should match their order in the file, each tag on a new line.
The number of spaces, newline characters (\n), or carriage returns (\r) does not affect the result.
The file does not have a CDATA tag. Each opening tag has a separate closing tag, and there are no self-closing tags.
Tags may have nested tags.

Example output:
Leela Turanga Leela Turanga Super girl

Tag templates:
<tag>text1</tag> <tag text2>text1</tag> <tag text2>text1</tag>

text1 and text2 can be empty

Requirements:

The program must read the file name from the console (use BufferedReader).
The BufferedReader used for reading input from the console must be closed after use.
The program must read the file's contents (use FileReader).
The file input stream (FileReader) must be closed.
The program must write to the console all the tags that match the tag specified by the argument passed to the main method.

package com.codegym.task.task19.task1918; /* Introducing tags */ import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String fileName = reader.readLine(); reader.close(); String tagName = args[0]; String tagNameStart = "<" + tagName; String tagNameClose = "</" + tagName + ">"; // String fileName = "C:/Users/Dan/Desktop/codegym test files/testTag.txt"; // String tagNameStart = "<span"; // String tagNameClose = ""; String combinedTags = ""; BufferedReader bufferedReader = new BufferedReader(new FileReader(fileName)); while (bufferedReader.ready()) { combinedTags += bufferedReader.readLine(); } bufferedReader.close(); // System.out.println(combinedTags); ArrayList<Integer> startIndexList = new ArrayList<>(); ArrayList<Integer> endIndexList = new ArrayList<>(); // adding the beginning and ending indexes to the list as per the ,as per the tag. Pattern pattern1 = Pattern.compile(tagNameStart); Pattern pattern2 = Pattern.compile(tagNameClose); Matcher matcher1 = pattern1.matcher(combinedTags); Matcher matcher2 = pattern2.matcher(combinedTags); while(matcher1.find() && matcher2.find()) { startIndexList.add(matcher1.start()); endIndexList.add(matcher2.end()); } // for (int i : startIndexList) { // System.out.print(i + " "); // } // System.out.println(); // for (int i : endIndexList) { // System.out.print(i + " "); // } // System.out.println(); // final logic to print each of the tags in new line. for(int i = 1; i < endIndexList.size(); i++) { int beginIndex = 0; int endIndex = 0; if (endIndexList.get(i - 1) > startIndexList.get(i)) { beginIndex = startIndexList.get(i -1); endIndex = endIndexList.get(i); System.out.println(combinedTags.substring(beginIndex, endIndex)); System.out.println(combinedTags.substring(startIndexList.get(i), endIndexList.get(i - 1))); } else { beginIndex = startIndexList.get(i); endIndex = endIndexList.get(i); System.out.println(combinedTags.substring(beginIndex, endIndex)); } } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

17 January 2021, 17:46

useful

I can explain the logic that I used in my code (after getting the data from the file): #1 set a current index to the first open tag of the files data #2 LOOP - 2a) got the next open tag was and the next closing task past the current index - 2b) checked if the open tag occurred before the closing tag (this means there is a nested tag, or multiple nested tags) - 2c) if 1b was true then I found the next open and the next close tags and check those with condition of 1b - 2d) if one b was false then I would print the string between the tag from step 1 and closing tag found and set the current index to past the index of the tag from step 2 So so lets say you had indices that indicated that the open and close occurred in this order: [o, o, c, o, c, c] ↑ Step 1 you would get the first open tag [o, o, c, o, c, c] ↑ ↑ Step two you would get the next open tag and next close tags that occur after the tag from step 1, compare which occurs first. Because the open is first you would repeat this step [o, o, c, o, c, c] ↑ ↑ Step two (repeat) get next two oepn/close tags. Once again the open occurs before the close so you would repeat again [o, o, c, o, c, c] ↑ Step 2 (repeat) get next 2.. but there is no more open tags. This means that this close is the tag you are looking for [o, o, c, o, c, c] ↑ ↑ Step 3 take the open tag from step one, the closing tag from step 2 and output the String between them, then go back to Step one and start again with the next open tag [o, o, c, o, c, c] ↑ Step 1 (repeat) start with the next open tag [o, o, c, o, c, c] ↑ ↑ Step 2 get next open and closing tags past Step 1's tag. closing occurs before open so this is the correct tag [o, o, c, o, c, c] ↑ ↑ Step 3 output the string between the open and close, go back to Step 1 repeat again as necessary.

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

18 January 2021, 13:29

Hey I tried to put that logic and changed my code.. still not passing.. please help me out.

public static void main(String[] args) throws IOException {
        boolean debug = false;
        String fileName, tagNameStart, tagNameClose;

        if(debug) {
            fileName = "C:/Users/Dan/Desktop/codegym test files/testTag.txt";
            tagNameStart = "<span";
            tagNameClose = "</span";
        } else {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            fileName = reader.readLine();
            reader.close();
            tagNameStart = "<" + args[0];
            tagNameClose = "</" + args[0];
        }

        StringBuilder combinedTags = new StringBuilder();

        BufferedReader bufferedReader = new BufferedReader(new FileReader(fileName));
        while (bufferedReader.ready()) {
            combinedTags.append(bufferedReader.readLine());
        }
        bufferedReader.close();

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

18 January 2021, 13:30

String data = combinedTags.toString().replaceAll("\r\n", "");
        System.out.println(data);

        data = data.substring(data.indexOf(tagNameStart) + 5);
        String[] splittedString = data.split(tagNameStart);

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

18 January 2021, 13:33

for (int i = 0; i < splittedString.length; i++) {
            if (splittedString[i] != null) {
                splittedString[i] = tagNameStart + splittedString[i];
                int incrementer = 1;
                int openingTagCounter = 1;
                int closingTagCounter = 0;
                int closingCountTrack;
                if (!splittedString[i].contains(tagNameClose)) {
                    while (i + incrementer < splittedString.length
                            && openingTagCounter != closingTagCounter) {
                        openingTagCounter = 0;
                        closingCountTrack = splittedString[i].lastIndexOf(tagNameClose);
                        splittedString[i] = splittedString[i] + tagNameStart + splittedString[i + incrementer];
                        splittedString[i + incrementer] = null;
                        incrementer++;
                        openingTagCounter++;
                        if (closingCountTrack > 0)
                            closingTagCounter++;
                        if (closingCountTrack != splittedString[i].lastIndexOf(tagNameClose)) {
                            closingTagCounter++;
                        }
                    }
                }

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

18 January 2021, 13:33

continuing the above

if (splittedString[i].indexOf(tagNameClose) != splittedString[i].lastIndexOf(tagNameClose)) {
                   System.out.println(splittedString[i]);
                   String[] nestedSplit = splittedString[i].split(tagNameStart);
                   for (int j = 0; j <  nestedSplit.length; j++) {
                       if (nestedSplit[j].contains(tagNameClose)
                               && nestedSplit[j].indexOf(tagNameClose) != nestedSplit[j].lastIndexOf(tagNameClose))
                           System.out.println(tagNameStart + nestedSplit[j].substring(0, nestedSplit[j].indexOf(tagNameClose) + 7));
                       else if (nestedSplit[j].contains(tagNameClose)){
                           System.out.println(tagNameStart + nestedSplit[j]);
                       }
                   }

               } else {
                   System.out.println(splittedString[i]);
               }

           }
       }

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

18 January 2021, 13:35

sorry had to paste it in multiple messages due to character limit. Or please check my entire code in the below link. https://paste.ofcode.org/BTVvcatqWwZvMnnR6xwCY

Guadalupe Gagnon

Level 37 , Tampa, United States

18 January 2021, 14:40

#1 The tag length is hard coded into the code expecting a length of 5. data = data.substring(data.indexOf(tagNameStart) + 5); The tags can be anything: <a></a><aLongTag></aLongTag> Also, there is a hard coded length, 7, on this line: System.out.println(tagNameStart + nestedSplit[j].substring(0, nestedSplit[j].indexOf(tagNameClose) + 7));

Guadalupe Gagnon

Level 37 , Tampa, United States

18 January 2021, 15:07

solution

#2 Outputting whole lines from the 'splittedString' array is not going to work. Take for example this input, where the tags are "<a" and "</a>": <a href="#cite_note-1">[1]</a> <a href="/wiki/">wiki<a href="1">2</a></a> After trimming the beginning and then splitting by the open tags, you end up with: href="#cite_note-1">[1]</a> , href="/wiki/">wiki, href="1">2</a></a>" and the first output ends up being the String in index one: <a href="#cite_note-1">[1]</a> This is because the code assumes that a spilt occurs right at a closing tag and an open tag. In the above example you have a secondary tag occurring right at the point of the split which is valid and not handled by the algorithm.

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

18 January 2021, 17:43

thank you Guadalupe.. im speechless! i hope i get better in time and see all of these bugs

Guadalupe Gagnon

Level 37 , Tampa, United States

18 January 2021, 18:00

Your code looks exactly like mine when I was around your skill level. Even today, when I encounter new problems that I haven't solved at least something similar to in the past, the code for my initial algorithm to solve that ends up being HUGE. It takes me a little while to improve that code down to something that is small and easy to read. It's funny, typically final algorithms that solve a problem are very simple.... however arriving at that final algorithm for the very first time is a real time consuming effort. Trust me, the greatest thing that will determine your overall ability in coding is experience.

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

19 January 2021, 04:03

thanks for sharing your insight :) it adds to my motivation.

Nouser

Level 36 , Germany

17 January 2021, 13:13

Yours works with max one nested tag. However they write 'Tags may have nested tags.' A nested tag is a tag and tags may have nested ones. Don't know how deep the validator is testing that.

Chandan Thapa

Level 22 , Dubai, United Arab Emirates

17 January 2021, 14:53

true i need to find out something that goes for many nested tags