I don't think that the end of the Second World War was completely 'hour zero' for Germany, because the Germans didn't start right out of nothing after the war.
The 'new' form of government has already been 'tested' before in the Weimar Republic and was only destroyed of Hitler's totalitarian idea of leading a state. So the Germans had a basis from which they could build up their new democratic government. And they used the old system, only in some points modified.
Secondly the German industry and infrastructure wasn't completely destroyed. The old machinery was still usable and people who have built militarily trucks before can build also civil trucks, they just have to change the labels.
Of course, the changes in life from Nazi-Regime to a democratic parliamental Government were great, but as we see the Germans did very well and managed to re integrate Germany in the world and world market very quickly.
The division of Germany in two separated states took place slowly and with little steps.
At first Germany was divided straight after WW II when the 4 winner countries occupied Germany. But it became clear that the British and French and American zones would cooperate in order to achieve a 'fully functional' Germany again, while the Russians wanted to carry through their ideas of 'democratic communism' in order to strengthen their USSR and to control the whole block of eastern European states.
Steps to the division of Germany were :
The last step was the construction of the German wall, which made it nearly impossible to escape from the east.
But as we know today, no wall exists forever if the pressure of the people who are restrained just demonstrate enough...Homework on the 10. Dec. 1992 in History