ExpandableArray.java

public class ExpandableArray {
    private int[] m_array;
    private int m_length;
    
    public ExpandableArray() {
        // First initialize to a capacity of 2
        m_array = new int[2];
        m_length = 0;
    }
    
    public int get(int i) {
        return m_array[i];
    }
    
    public int size() {
        return m_length;
    }
    
    public void add(int value) {
        if (m_length == m_array.length) { // Not enough space
            // Create a new array with double the size of the old array
            int[] newArray = new int[m_array.length * 2];
            
            // Copy old array into the new one
            for (int i = 0; i < m_length; i++) {
                newArray[i] = m_array[i];
            }
            
            // Replace the old array with a new one
            m_array = newArray;
        }
        
        m_array[m_length] = value;
        m_length++;
    }
}