What should students be taught first when first learning sorting algorithms? [closed]

Answer 1

I thought selection sort was the simplest to comprehend, and IMO would be the best to introduce sorting.

I think it would be silly to not teach them at least one O(nlog(n)) sorting algorithm, along with an explanation of big O notation.

Answer 2

I'd start by showing insertion sort. Everyone who's sorted a hand of cards (which is basically everybody) knows this sort. Plus it's doesn't have the abysmal performance of bubble sort.

Answer 3

They should be first asked to implement their own sorting algorithm - from scratch, without reference to any existing algorithm beforehand. Doing this will teach them about sorting way more than telling them of an algorithm that they wouldn't have any idea how it was derived.

Answer 4

Uhm... sorting algorithms are really a intuitive, concrete way of teaching some good lessons about Big O notations, optimization, common sense and computer science in general, and maybe a "bubble sort" + "select sort" + "merge sort" approach might be useful, for comparison. I think the most intuitive (and efficient in many cases) is the select sort.

Answer 5

Let your students decide.

Before introducing any sorting algorithms, give each student some playing cards, maybe 10 or so. Then ask them to sort the cards. Have them write down the steps they take, which will essentially be their algorithm. Likely they'll discover insertion or selection sort. You can also ask them to estimate how many steps their sort would take if they had 100, or 1000 cards, which is a good lead into big O notation.

PS - does anybody think they'd discover bubble sort?

Answer 6

I learned Bubble Sort first -- I think if you do only one, you probably need to do one of the O(n^2) algorithms because they are easier to understand.

There are a lot of sort visualizers out there to help quickly show a comparison:

• http://www.cs.ubc.ca/~harrison/Java/sorting-demo.html
• http://math.hws.edu/TMCM/java/xSortLab/
• http://vision.bc.edu/~dmartin/teaching/sorting/anim-html/all.html
• http://maven.smith.edu/~thiebaut/java/sort/