This question was found on StackOverflow. I wanted an algorithmic problem to teach what programming could be. There is a few ways to solve it here.
There are given n boxes, each one has fixed weight and strength (both given in kg). Box's strength tells us what is the maximum weight it can bear. We have to form the highest pile of given boxes (each of them has the same height).
You should propose an algorithm that will always give an optimal solution, which is the longest sequence of k boxes (k <= n).
It is what PileExplorer in the test_helpers.rb file is about.
It tries every state of the problem blindly, keep the valid states,
and find the solution looking at all the valid states.
Trying to show an alternative to the bruteforce (which is very long) by mimicing and human brain. Also this show how to use recursion. The point is, there is no warranty that the result would be the best solution...
In the Explorer class, there is a new algorithm that does a smarter
partition and only build possible piles.