Draw the recursion tree when n = 8, where n represents the length of the array, for the following recursive method: int sum(int[] array, int first, int last) { if (first == last) return array[first]; int mid = (first + last) / 2; return sum(array, first, mid) + sum(array, mid + 1, last); } Determine a formula that counts the numbers of nodes in the recursion tree. What is the Big-theta for execution time? Determine a formula that expresses the height of the tree. What is the Big-theta for memory? Write an iterative solution for this same problem and compare its efficiency with this recursive solution.