Sorting Algorithms.

• Bubble sort - slowest, worst case and average complexity O(n2)
                        compare pairs one by one
• Selection sort - find the smallest and swap, combination of searching and sorting.
                        complexity n(n-1)/2
• Insertion sort - worst case O(n2), efficient for small data sets
                        grow the sorted output list by taking one input at each repetition.
                        use the smallest O(1) of additional memory space
• Quick sort - fastest, also known as partition-exchange sort and is a divide and
                        conquer algorithm. It divides the list into two and recursively sort the sublists.
                        complexity in the average case is O(n log(n)) and worst case O(n2)
• Merge sort - divide the unsorted array into n partitions of one element and recursively
                        merge them into sorted list at the end.
                        It is a fast, stable sorting with guaranteed O(n*log(n)) efficiency but it
                        requires additional scratch space proportional to the size of the array.