Check to make sure the hinges are properly set into their mortises. Sometimes they get re-installed with lippage over the mortise and it'll throw the swing off.
Also, it's possible that the hinge leave got installed backwards. Yes, I've seen it before.
Other possible causes that have nothing to do with the floor install.
High humidity caused the doors to swell, causing binding.
Painting behind the hinge leafs while they were removed.
Leaning the doors against the wall while removed, causing them to warp.