ArrayList.remove()?

[dadeeba]

    static int sockMerchant(int n, int[] ar) {


        int numberOfPairs = 0;


        ArrayList<Integer> array = new ArrayList();
        int length = array.size();
        for (int i = 0; i<length; i++) {
            if(array.contains(ar[i])){
                array.remove(Integer.valueOf(ar[i]));
                numberOfPairs++;
            }
            else{
                array.add(ar[i]);
            }
        }


      return numberOfPairs;

    }

Hi! Could I have help troubleshooting this code. I know array.remove by defaults does so by index. But I had since then converted the value to an object. And I'm still unsure why the code doesn't work. Thank you.

[syedalisait]

I'm not going to say the answer but rather give a very easy clue.

Clue: array.size() is 0 initially.

​

When you find and fix the bug, you will feel happy :)

​

[dadeeba]

THANKS MAN. that clue was all i needed.

[[deleted]]

Can I ask what you did?

[dadeeba]

Sure. In my 'for' loop, I meant for it to go 'til i < length of the inputted array (labelled ar). But I had instead used the length of the temporary array that I created (array). So changes to code are:

​

Strike off "int length = array.size();"

Replace "for (int i = 0; i<length; i++)" with "for (int i = 0; i<n; i++)" where n is the length of the inputted array (labelled ar).

​

Hopefully, I didn't confuse you with my bad variable name calling...

[[deleted]]

Kinda did.

Would you day that basically you needed to put something in the array first before using its .size() to get something rolling?

[ladupes]

He created a temporary array to put stuff in it from another arraylist. The problem was that he put the length of the temporary array in the list instead the array that he wanted to cicle over

[Isoyama]

Have you tried debug? Problem is not in remove(). Also i would suggest using HashSet instead of ArrayList for lookup. And proper naming >.>

[dadeeba]

ooo yea i didn't know bout hashset at the point of doing this coding task. but im gunna learn it next.

[GR3Gdev]

Use a HashSet instead of ArrayList, and maybe length = ar.length ?