3. There is a simple, but inefficient, algorithm, called bubble-sort, for sorting a sequence S
of n comparable elements. This algorithm scans the sequence $n - 1$ times, where, in each
scan, the algorithm compares the current element with the next one and swaps them if
they are out of order. Give a pseudo-code description of bubble-sort that is as efficient as
possible assuming S is implemented with a doubly linked list. What is the running time
of this algorithm (using the Big-Oh notation)?
hint: Avoid index-based operations.
