A problem that i've faced in an INterview!

Question

Hi,
In AN interview i was told tested my .NET skill by asking write an application within time frame. I was give a specification (an old fashion specification) and i asked the interview / tester couple of question that what sort of methodologies that i should use to design the application such OOP, designer patterns or procedural or object based..... he told me that to write the application from the way i know it.... i was confused and i followed middle ground so that i used partially OO and Partial Desing pattenr techniques...... He didnt event ask for a model.... however i fisnihed my app within 2-3 hours, it worked but i was happy the way i had to design and code it....
I was thinking that if i used OO Design techniques with Design patterns it would take more time to write the application that why i followed the middle ground technique (partial everything) though i finihsed my application i havent received any feedback of my application.....
In these kinds of interviews, what sort of technique that i should follow to code?
 
TY in advance