In computer science and discrete mathematics, an inversion is a pair of places in a sequence where the elements in these places are out of their natural order. So, if we use ascending order for a group of numbers, then an inversion is when larger numbers appear before lower number in a sequence.

Check out this example sequence: (1, 2, 5, 3, 4, 7, 6) and we can see here three inversions - 5 and 3; - 5 and 4; - 7 and 6.

But there are no negative numbers -5 in the list. It is advisable to correct this defect in the condition