public class OurSortedArrayList {

    // This is the array in which we'll store the integers.
    Integer[] data = new Integer [1];

    // Initially, there are none.
    int numItems = 0;


    public void add (Integer K)
    {
        if (numItems >= data.length) {
            // Need more space. Let's double it.
            Integer [] data2 = new Integer [2 * data.length];
            // Copy over data into new space.
            for (int i=0; i<data.length; i++) {
                data2[i] = data[i];
            }
            // Make the new array the current one.
            data = data2;
        }
        
	// Now find the right place.
	int k = numItems;
	for (int i=0; i<numItems; i++) {
	    if (data[i] > K) {
		k = i;
		break;
	    }
	}
	// Insert at k, by shifting everything to the right.
	for (int j=numItems; j>k; j--) {
	    data[j] = data[j-1];
	}
        data[k] = K;
        numItems ++;
    }


    public int size ()
    {
	return numItems;
    }


    public boolean contains (Integer K)
    {
	return binarySearch (data, K, 0, numItems-1);
    }    


    static boolean binarySearch (Integer[] A, int value, int start, int end)
    {
        // Only need to check if the interval got inverted.
        if (start > end) {
            return false;
        }
        
        // Find the middle:
        int mid = (start + end) / 2;

        if (A[mid] == value) {
            return true;
        }
        else if (value < A[mid]) {
            // Search the left half: A[start],...,A[mid-1]
            return binarySearch (A, value, start, mid-1);
        }
        else {
            // Search the right half: A[mid+1],...,A[end]
            return binarySearch (A, value, mid+1, end);
        }
    }


    public String toString ()
    {
        if (numItems == 0) {
            return "Empty";
        }
        
        String s = "List: ";
        for (int i=0; i<numItems; i++) {
            s += " " + data[i];
        }
        return s;
    }


    public static void main (String[] argv)
    {
	OurSortedArrayList list = new OurSortedArrayList();
	list.add (3);
	list.add (1);
	list.add (2);
	list.add (4);
	System.out.println (list);
	System.out.println ("2 in list? " + list.contains(2));
	System.out.println ("5 in list? " + list.contains(5));
    }
    

}