Problem of the Day

Wednesday, April 1, 2026

Problem:

Consider the following method, which is intended to take a value from an ArrayList at position n and move it to the end of the ArrayList, leaving the other items in their original order.

/**
 * Moves the item at index n to the end of the ArrayList, leaving
 * the other items in their original order
 * @param nums an ArrayList of Integers
 * @param n an index value indicating which item should be moved
 *          to the end of the list
 * PRECONDITION: The ArrayList has a length > 0.
 * PRECONDITION: n is a legal index
 */
public static void endOfTheLine(ArrayList nums, int n)
{
    /* missing code */
}

Which of the following could be used to replace /* missing code */ so that the method will work as intended?

1. 
   

   nums.remove(n);
   nums.add(n);

2. 
   

   int tmp = nums.get(n);
   for (int i = n; i < nums.size() - 1; i++)
       nums.set(i, nums.get(i + 1));
   nums.set(nums.size() - 1, tmp);

3. 
   

   nums.add(nums.get(n));
   nums.remove(n);

1. I only
2. I and II only
3. II only
4. II and III only
5. I, II, and III

Show solution: