The other day, out of curiosity I was measuring the current wave shape of a laptop charger. The wave shape indicated a spike only in one half cycle. I'm guessing half wave rectifier here.
One thing that kept me thinking was Why would someone prefer a half wave over full bridge and full wave rectifier? I'm guessing lower BOM cost / the 1.4V drop across the diodes.
Or was it just the designers choice and there's no point in thinking about it ?