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

Answer 1

I would compare and contrast an o(n-squared), like selection sort with a o(n log n) sort like quicksort.

But if they aren't computer science people and don't necessarily intend to be then just show an easy to understand sort like selection or bubble.

Answer 2

Selection sort is probably the most straightforward sorting algorithm to teach and simplest to grasp. It's also a great example of why simple solutions are not always the best, which could lead into a discussion of more interesting and faster sorts like mergesort and quicksort.

Answer 3

I'd teach Bubble sort if I had to pick only one, since it's simpler to grasp (I think). However, the most valuable thing I got out of studying the various sorting algorithms was that there's more than one way to do it (which eventually led me to Perl, but that's another story), each with advantages and drawbacks. So, learning a single sorting algorithm might be a way to miss the critical aspect of the whole thing.

Answer 4

Er, you should be giving them an O(n^2) and an O(n log n) sort. Bubble and Heap would be my picks.

Answer 5

IntroSort is a great algorithm to teach as well, once students have learned to understand Quick and Heap sort. IntroSort (short for Introspective sort) starts as a QuickSort and switches to a HeapSort if the recursion depth exceeds a level based on the logarithm of the number of elements being sorted.

Overall, you get the best of the Quick and Heap sort worlds and a worst case running time of O(n log n).

IntroSort on Wikipedia

Answer 6

Bubble sort is the classic, and it is very easy to grasp why it works.

But unless this is a very introductory course then it should include an overview of other sorting algorithms since this is by far the best way to show the trade offs involved in algorithm design and explain best case vs worst case vs average behaviour (both runtime and memory).