JOB ORDERING with dependency

Created by Jan Padrta

At first I thought about pure Ruby application but I rejected this solution because I love Rails and the idea of web interface with the possibility to insert jobs and dependencies.

The solution with array of arrays came into my mind immediately after reading the task. I was thinking about some [[‘a’],,[‘c’]] array and method to order it according to dependencies.

I created the rspec tests following the given examples (later I added some new ones as a new possibilites arose) and started developing.

Initial solution was a little tough coded but the principle was correct:

• loop through the array

• if there is dependency then find the position of it

• delete the element and insert it in the correct place

Unfortunatelly I switched the comparison and it wasn’t working. So I started to experiment with the flow and after few debug steps I realised what I built wrong. Then it was relatively easy and quick. I corrected the flow/condition and refactored the main method. Then I added valid? and circular? methods to find out the errors and it was done. All specs were green and web interface was showing correct results.

Uploading to GitHub with RubyMine, which I use, was simple and automatic.