#48in24: Add approaches to Knapsack

[sanderploegsma]

The Knapsack exercise on the Java track is being featured in the #48in24 challenge, which means that we expect an influx of students attempting to solve it during that week.

It would be nice if the exercise contains some more content by that time.
One example of this is to add one or more approaches to the exercise, so that students can dive in deeper after they have solved it themselves.

For an example of how approaches have been added to other practice exercises, take a look at the approaches for the Leap exercise.

[kahgoh]

I'd like to work on this one.

The two main approaches I am currently aware of:

• A recursive approach like this one or this one
• Iterative approach, building a table of max values, like this one

[sanderploegsma]

Great, go ahead!