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

Answer 1

Quicksort is definitely another very simple-to-understand sorting algorithm, and it's a cinch to implement it. It has in-place amd "out-of-place" versions that are fun to think about. And it's quick.

Quick enough for you, at least, old man.

Answer 2

It would be radix sort. Because it is surprisingly easy and yet non-obvious. Things like that just have to be taught.

Answer 3

If you want to teach the concept of sorting, then I believe you must teach at least two different ways of sorting -- otherwise the students will think that sorting is just about the one way you taught them.

I think the students would get the most value out of learning a classic O(n^2) algorithm (preferably insertion or selection sort, but please not bubble sort, which has no justification for being used in real applications), as well as a divide-and-conquer, O(nlogn) algorithm such as quicksort or merge sort.

If you're worried that these sorts will be too hard to teach your students, have a look at these activities from Computer Science Unplugged, which are designed for elementary school students.

Answer 4

I think that only teaching one sort is crippling. Remember that Everything Is Fast For Small n, so in terms of teaching a sort, it is not a question of performance, but understanding the algorithm.

I think the intro should be the bubble sort to introduce the concept, but at a minimum introduce another sort to get the students thinking about other ways to perform the task. Make sure they understand the tradeoff in performance and code complexity and that there are different tools for different situations.

Answer 5

Have everyone bring in a deck of cards, and pick out one suit. Divide into teams of two. One shuffles the 13 cards, and lays them face down in a row. The partner gets to point to two of the cards. The other picks them up, looks at them, and either says "In order" or "Not in order" The parter then can tell him to swap them, and lay them down again (face down)

The job of the partner is to sort the cards in order (something you will need to define up front).

When the parner thinks they are sorted, he says "Stop". The other turns the cards face up, and they check.

When this is done, discuss what worked for everyone. Then talk about BUBBLE SORT vs SELECTION sort

Then talk about QUICK SORT.

Have them try each of them out, with their suit of cards.

Answer 6

I just did that last week with my kid I ask him to come up with their own sorting algorithm, and asked how long it would take to sort a deck of cards using his method. Then I showed him Bubble Sort ( the easiest to explain to a kid) " It's a bubble!" and made him count the steps again. He realized then it was easier and faster.

Then If you want you can teach more advanced ones ( Quicksort is the most surprising ), Ideally you should teach three at least that are different ( not variation of the same)