Please answer both a and b

3. Consider QuickSort on the array A[I1:m] and assume that the pivot element x (used to split the array Allo:hi] into two portions such that all elements in the left portion Allo:m] and all elements in the right portion A[m:hi] are x) is the penultimate element of the array to be split (i, e., hi-1). Construct an infinite sequence of numbers for n and construct an assignment of the numbers 1...n to the n array elements that causes QuickSort, with the stated choice of pivot, to (a) execute optimally (that is A[lo:m] and A[m:hi] are always of equal size) (b) execute in the slowest possible way are x