I have been lifting for the last six months. Doing 6-7days/week (chest/triceps/shoulders),(back/biceps),(legs) body split. I really like my progress and the muscle mass I have gained. However, due to new job assignment it means that for the next six months I only have time to lift on Wednesdays,Thursdays and Fridays. What best 3day/week course I can go for so I can at least keep the progress I have achieved and maybe gain some more.
Check this article out, it gives a pretty good overview of different 3-day splits. This article/section mentions that 10-20 sets per major muscle group per week is enough to build muscle, 10-12 should suffice for beginners (which you definitely still are). So I would say either approach in the first article can get you some more gains, a lot of it will come down to exercise selection and training intensity (less training days = less volume, so you might wanna up the intensity a little).
Whichever split you chose, I would suggest that you do a lot of compound / free weight movements. They offer a great "bang for your buck" and will enable you to fit more into a single session, compared to implementing tons of isolation exercises.
In my experience, full body works pretty well because of the high frequency. Plus, training like this makes me feel more athletic and is fun to do (also important, gotta enjoy training as well).