Failing to pass second requirement, not sure why...

Question about the task

Remove duplicate strings

Java Syntax, Level 6, Lesson 4

Under discussion

I got correct output from the code but I'm failing to pass second requirement. Has anyone got any idea why's that?

In this task, you need to:

Read 6 strings and fill the strings array with them.
Remove duplicate strings from the strings array, replacing them with null (null, not the string "null").

Examples:
The array after reading the strings:
{"Hello", "Hello", "World", "Java", "Tasks", "World"}

The array after removing duplicate strings:
{null, null, null, "Java", "Tasks", null}

Requirements:

In the main(String[]) method, read 6 strings from the keyboard and fill the strings array with them.
In the main(String[]) method, remove (meaning, overwrite with null) any duplicated elements in the strings array.

package en.codegym.task.pro.task05.task0508; import java.util.Scanner; /* Remove duplicate strings */ public class Solution { public static String[] strings; public static void main(String[] args) { Scanner console = new Scanner(System.in); strings = new String[6]; for(int i = 0; i < strings.length; i++){ strings[i] = console.nextLine(); } for(int i = 0; i < strings.length; i++){ for(int a = i + 1; a < strings.length; a++){ if(strings[i] == null) break; if(strings[i].equals(strings[a])){ strings[i] = null; strings[a] = null; } } } for (int i = 0; i < strings.length; i++) { System.out.print(strings[i] + ", "); } } }

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Luis Miguel Rodriguez Ugarte

Level 20 , France

17 May 2022, 18:33

Hi I follow this approach, maybe is not the best but it works for me, hope it helps somehow.

//First do a for loop in order to fill the array with strings
// create a int variable for count the occurrences, it will help you later to override the values of the array //Strings.
//create another Array "Counting"in order to save the occurrences. my logic is the following:
// every time I find a match while doing the comparison I put the value of such an index to 1.
//e.g for given array {"hello,"world","hello"}
//I added the value for the array"Counting" -> counting[0]=1, counting[1]=0, counting[2]=1
//do a for loop for the whole array and then a nested for loop to compare
//each value of the array with each other, when you get a match increase the count variable and apply logic explained above
// after doing the loop I just make a comparison if int ocurrences > 0, do a for loop for the array"counting"
//and replace the values with array Strings to null...like below
        if (count > 0){
            for (int t=0;  t < arrayN.length ; t++){
                if (arrayN[t] > 0){
                    strings[t] = null;
                }
            }
        }

Lisa L

Level 47 , Nuremberg, Germany

16 May 2022, 21:45

What if there are three dupes? Do all three have to be removed? I do not know this taks... so this is just a question.

Krzysztof Kasperek

Level 20 , Drammen, Norway

17 May 2022, 11:32

I'll try to modify code so it will cover multiple dupes. We'll see if it passes.

Krzysztof Kasperek

Level 20 , Drammen, Norway

17 May 2022, 11:52

The code covers multiple dupes but still doesn't meet the requirements.

String mod = null;
        for(int i = 0; i < strings.length; i++){
            for(int a = i + 1; a < strings.length; a++){
                if(strings[a] == null)
                    break;
                if(strings[i] != null){
                    mod = strings[i];
                }
                if(mod.equals(strings[a])){
                    strings[i] = null;
                    strings[a] = null;
                }
            }

        }

Lisa L

Level 47 , Nuremberg, Germany

17 May 2022, 12:50

the code does not work correctly... try 1, 0, 1, 0, 2, 3, the zeros remain. Maybe think about rewriting it from scratch. As it currently is, it is hard to understand, way to complex for its purpose. What about this approach...

outer loop 0 - length:
     int occurrencs = 0;
     inner loop 0 - length;
         count occurences
     end inner loop

    if (occurrencs > 1)
        inner loop 0 - length;
            assign null to all occurrences
        end inner loop
end outer loop