removeArrayDuplicates()

Step 1: Understand the Problem to Solve

The task at hand is to write a Java function that can take an Array as input and return a new array that has no duplicate elements. Java arrays are fixed in size. Therefore, we will need to use a data structure, like ArrayList or HashSet, that can dynamically adjust the size. HashSet is particularly useful since it not only manages the size but also automatically eliminates duplicates.

// Understand the problem
public static int[] removeArrayDuplicates(int[] numbers) {

}

Step 2: Use the HashSet Class

Initialize a new HashSet object. Pass our array to it. The HashSet will automatically remove the duplicates for us.

// Use HashSet to remove duplicates
HashSet<Integer> set = new HashSet<>();
for (int number : numbers) {
    set.add(number);
}

Step 3: Convert HashSet Back to Array

We need to return the output as an array. To do this, we first convert our HashSet to an ArrayList. Because ArrayList has a method toArray(), we can easily change it back to an array.

// Convert HashSet back to Array
ArrayList<Integer> list = new ArrayList<>(set);
Integer[] output = list.toArray(new Integer[0]);

Step 4: Convert Integer Array to int Array

In Step 3, our method toArray() turned our ArrayList into an Integer array. However, our function needs to return an int array not Integer. In the last part we'll be converting our Integer array into int array.

// Conversion Integer array to int array
int[] finalOutput = new int[output.length];
for (int i = 0; i < output.length; i++) {
    finalOutput[i] = output[i];
}

Step 5: Return finalOutput and Done

Finally return finalOutput which is our array without duplicate values.

// Final version of our function
public static int[] removeArrayDuplicates(int[] numbers) {
    HashSet<Integer> set = new HashSet<>();
    for (int number : numbers) {
        set.add(number);
    }

    ArrayList<Integer> list = new ArrayList<>(set);
    Integer[] output = list.toArray(new Integer[0]);

    int[] finalOutput = new int[output.length];
    for (int i = 0; i < output.length; i++) {
        finalOutput[i] = output[i];
    }
    return finalOutput;
}