Given an array a that contains only the numbers 1 and 1-. Define - an inverse pair is a pair of indices i and j such that i < j and a[i] = -1 and a[j] = 1 or a[i] = 1 and a[j] = -1. Write a method whose signature - public int howManyOpposites(int[] a) The method will receive as a parameter an array filled with the numbers 1 and 1- and will return the number of inverted pairs present in the array. For example, for the following array: -1 1 -1 -1 1 1 The method will return 9, because there are nine inverted pairs: (0, 1), (0, 4), (0, 5), (1, 2), (1, 3), (2, 4), (2, 5), (3, 4), (3 , 5) Please note - the method should have the best possible runtime efficiency, and the best possible memory efficiency. A method that is not maximally efficient will not receive full points. B. (5 points) What is the runtime efficiency of the method you wrote? Explain your answer.