ALGORITHM Quicksort(A[l..r]) //Sorts a subarray by quicksort //Input: Subarray of array A[0..n − 1], defined by its left and right // indices l and r //Output: Subarray A[l..r] sorted in nondecreasing order if l < r s = Partition(A[l..r]) //s is a split position Quicksort(A[l..s − 1]) Quicksort(A[s + 1..r]) The above code is the quicksort algorithm. Perform a time complexity analysis for quicksort. You need to explain 1) what makes a worst case, what makes a best case, 2) the time complexity for both the worst case and the best case, 3) how to avoid the worst case in practice.

ALGORITHM Quicksort(A[l..r])
//Sorts a subarray by quicksort
//Input: Subarray of array A[0..n − 1], defined by its left and right
// indices l and r
//Output: Subarray A[l..r] sorted in nondecreasing order
if l < r
s = Partition(A[l..r]) //s is a split position
Quicksort(A[l..s − 1])
Quicksort(A[s + 1..r])

The above code is the quicksort algorithm.
Perform a time complexity analysis for quicksort. You need to explain 1) what makes a worst case, what makes a best case, 2) the time complexity for both the worst case and the best case, 3) how to avoid the worst case in practice.