The TIME/Life account of WW2 writes that the Nazis over-ran Denmark in three hours.
I’ve read that the Nazi invasion of Denmark was a bunch of German soldiers who crossed the border in civilian clothes, spread out though the small nation, and at a certain time, took off their overcoats and conquered Denmark firing few if any shots. That said, Denmark was the only conquered nation that actively tried to protect its Jewish population and insisted on inspecting the camps where Jewish Danes were interned.