Start small. Write out by hand the solutions to smaller problems such as groupSize(1, 6), groupSize(1, 7), groupSize(1, 8), and so on. As you do so you may see a certain kind of pattern.

As per ferencDobi's comment, the random tests make this harder than a typical 7 kyu kata.

Ah, ok. Thanks for all the TypeScript katas :)

I did this one by defining the getters and setters via Object.defineProperties in the constructor (as a workaround for not yet being able to transpile to ES5+). But now I'm getting these errors when attempting the kata:

../home/codewarrior/spec.ts(13,20): error TS2304: Cannot find name 'Cube'.
../home/codewarrior/spec.ts(43,18): error TS2304: Cannot find name 'Cube'.

Can you say or hint towards how quickSort([3,2,1]) results in four comparisons? I'm using the algorithm as described and only count three.

This is bad if only the length and width are passed to new Cuboids…oops.