"First come, first serve(d)" [closed]

Solution 1:

The second is correct. It is a form of "Those who come first are served first."

Solution 2:

As I have always been under the impression it is the former "First come, first serve", I have just google-searched the phrase.

The search returns most results confirming @Michael Blaustein's answer, with websites like Wikipedia containing the phrase "First Come, First Served" and so it seems this is the correct, original form.

You can also notice a few entries using "First come, first serve" (without the 'd') on forums and in newspaper articles and titles which suggests, as I have come to know, this version is also commonly used.