Question
Add the following method to the ArrayIntList class from this chapter.
Write a method called printInversions that lists all inversions in a list of integers. An inversion is a pair of numbers in which the first appears before the second in the list, but the first is greater than the second. Thus, for a sorted list such as [1, 2, 3, 4] there are no inversions at all, and the method would produce no output. Suppose that a variable called list stores the values [4, 3, 2, 1] . The call of list.printInversions(); would print many inversions:
(4, 3)
(4, 2)
(4, 1)
(3, 2)
(3, 1)
(2, 1)
The inversions can appear in any order, so this is just one possible correct output. You must reproduce this format exactly, but the inversions can appear in any order. You may assume that the list has no duplicates.
Answer
public void printInversions()
{
for(int i = 0; i < size - 1; i++)
{
for(int j = i + 1; j < size; j++)
{
if(elementData[i] > elementData[j])
{
System.out.println("(" + elementData[i]
+ ", " + elementData[j] + ")");
}
}
}
}