Euler Projects 18 and 67 require the use of arrays or other similar data structures. You are given a triangle of numbers, and your job to find the maximum sum traveling from the tip to the base of the triangle. Project 18 has a height of 15, problem 67 has a height of 100. To accomplish this, you need to set up the triangle as a tree structure (hence the array) and work the problem backwards from base to tip.
http://projecteuler.net/index.php?section=problems&id=18
http://projecteuler.net/index.php?section=problems&id=67
The small basic solution can be imported from the ID: XBN618