A good answer might be:
The problem has been solved when you are at the mall entrance.
Two Parts to Recursion
Of course you know how to cross a parking lot. You would
probably describe the process as "...keep walking until you reach the entrance."
Let us describe the solution in more detail:
- If you are one step from the mall, take that step and you are done.
- If you are further than one step from the mall, divide the distance into two parts:
Now take a step and then cross the remaining distance.
- a single step, and
- the remaining distance.
I've described the solution in a recursive style.
There are two parts to recursion:
- If the problem is easy, solve it immediately.
- If the problem can't be solved immediately,
divide it into smaller problems, then:
- Solve the smaller problems by applying this procedure to each of them.
The over-all strategy is to find some easily applied action that
breaks the problem into smaller pieces. Some of the pieces can
be dealt with immediately; others need to be further broken up.
Say that you have a small rock that you wish to destroy. How
can you do this?