import java.util.ArrayList;
import java.util.Arrays;

public class ArrayListExercise {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		ArrayList a = new ArrayList();
		a.add("one");
		a.add("two");
		a.add("three");
		a.add("four");
		System.out.println("Before: " + Arrays.toString(a.toArray()));
		expand(a);
		System.out.println("After: " + Arrays.toString(a.toArray()));
	}

	/**
	 * inserts the element at index i i times after that element
	 * @param list the ArrayList to expand
	 */
	public static void expand(ArrayList list) {
		int count = 0;
		for (int i = 0; i < list.size(); i += count) {
			Object element = list.get(i);
			for (int k = 1; k <= count; k++) {
				list.add(i, element);
			}
			count ++;
		}
	}

}