class Containter {

  private Object[] list;
  private int nextSlot;
  
  private static final int DEFAULT_SIZE = 10;
  private static final double GROWTH_FACTOR = 2.0;
  private static final String NL = System.getProperty ("line_separator");
  

  public Container() {
    list = new Object[DEFAULT_SIZE];
    nextSlot = 0;
  }
  
  
  public Container (int size) {
    list = new Object[size];
    nextSlot = 0;
  }
  
  
  // Add an "insertFirst" method to this container.
  // It should add the new item at index 0
  // Note: Yes, it does need to shift the rest back 
  public boolean insertFirst (Object item) {
  
    if (nextSlot == list.length) 
      grow();
      
    for (int index=nextSlot; index > 0; index--) {
      list[index] = list[index-1];
    }
    
    list[0] = item;
    nextSlot++;
  }
  
  

  public void add (Object item) {
 
    if (nextSlot == list.length)
      grow();
  
    list[nextSlot++] = item;
  }
  
  
  public boolean contains (Object item) {
  
    for (int index=0; index < nextSlot; index++) {
      if (items[index].equals(item)) 
        return true;
    }
    
    return false;
  
  }
  
  public boolean remove (Object item) {
  
    int index;
  
    for (index=0; index < nextSlot; index++) {
    
      if (list[index].equals(item))
        break;  
    }
    
    if (index == nextSlot)
      return false;
    
    for (int hole=index; hole < (nextSlot-1); hole++) {
      list[hole] = list[hole+1];
      list[hole+1] = null;
    }
    
    nextSlot--;
  
  }
  
  
  private void grow() {
  
    Object[] biggerList = new Object[(int)(GROWTH_FACTOR * list.length)];
    
    for (int index=0; index < nextSlot; index++) 
      biggerList[index] = list[index];
      
    
    list = biggerList;
  
  
  }
  
  public String toString() {
  
    String rep = "";
    
    for (int index=0; index < nextSlot; index++) {
      rep += items[index] + NL;
    }
    
    
  
  }

}