jeanlange / problem_5 Goto Github PK

Here's a solution to problem #5, found here:

Write a program that outputs all possibilities to put + or - or nothing between the numbers 1, 2, ..., 9 (in this order) such that the result is always 100. For example: 1 + 2 + 34 – 5 + 67 – 8 + 9 = 100.

I found 11.

I went about it using:

• TDD
• recursion
• starting with a smaller version of the problem.

Take a look at

• the git history to see how it progressed (my design changed a lot at the beginning, and continued to change throughout)
• the tests to see how to use it and what it can do.