Remove int at index in array for java powerball game

Question

Almost done making Powerball game, but theres a semantic error. Trying to compare two arrays of 5 ints and return number of matches. However if there is a duplicate number the number is matched multiple times. I need to delete both numbers after they are matched.

I tried using arraylist as suggested on here but arraylist is "Unused import statement" and .remove is "cannot resolve method"

import java.util.ArrayList;

for (int i = 0; i < 5; i++) {
     for (int j = 0; j < 5; j++) {
                if (balls[i] == yballs[j]) {
                    match++;
                    balls.remove();
                    remove(yballs, yballs[j]);
                }
            }
        }

public static int[] remove(int[] symbols, int c) {
    for (int i = 0; i < symbols.length; i++) {
        if (symbols[i] == c) {
            int[] copy = new int[symbols.length-1];
            System.arraycopy(symbols, 0, copy, 0, i);
            System.arraycopy(symbols, i+1, copy, i, symbols.length-i-1);
            return copy;
        }
    }
    return symbols;
}

Answer 1

As a solution to use ArrayList

You could populate the 2 ArrayLists to represent the two collection of balls and the one to hold the matches:

List<Integer> balls = new ArrayList<Integer>();
List<Integer> yballs = new ArrayList<Integer>();
List<Integer> matches = new ArrayList<Integer>();

balls.add(<ball number>);
...
yballs.add(<ball number>);
...

Then you would go through each ArrayList as:

for (Integer ballNumber : balls) {
    for (Integer yballNumber : yballs) {
        if (ballNumber == yballNumber) {
            matches.add(ballNumber);
        }
    }
}

And to remove all the duplicates from both List s:

balls.removeAll(matches);
yballs.removeAll(matches);

If you don't want to remove all of them and just remove one of the duplicates, you can do:

for (Integer match : matches) {
    balls.remove(match);
    yballs.remove(match);
}