The bubble sort is O(n2 ). Like selection sort, bubble sort won’t perform any swaps if the list is already sorted. However, bubble sort’s worst-case behavior for exchanges is greater than linear. The proof of this is left as an exercise for you. You can make a minor adjustment to the bubble sort to improve its best-case performance to linear. If no swaps occur during a pass through the main loop, then the list is sorted. This can happen on any pass, and in the best case will happen on the first pass. You can track the presence of swapping with a Boolean flag and return from the function when the inner loop does not set this flag. Write the modified bubble sort function. Create a list that contains 20 values from 1 to 20 in random order and test your modified bubble sort function.