Can I apply for deferred action for young people if I have not lived continuously for 5 years?

Your application for a work permit under the Deferred Action Process for Young People will go very smoothly if you have lived continuously in the United States since June 15, 2007.  Every time you are dealing with bureaucrats it is best to have clear cut situations, but if you are one of those with unusual situations that you did leave US and then returned and continued with your education or life, there are exceptions available.

While it is hard to believe that many undocumented immigrants had the liberty to leave the country and reenter, it is possible to do so by abusing a tourist visa.  The USCIS is saying that if these visits were brief (no details are available on what that means and this is where prosecutorial discretion comes in to play but I would assume that a few days or weeks for the right reasons will quality) and innocent (again no information on what that means but my best guess is that you left the country to tend to a sick family member or to attend a funeral or to complete some essential paperwork or something along those lines) and were undertaken for humanitarian purposes, exceptions will be granted.

Once again, at this time, USCIS has not qualified what it means by humanitarian purpose, but we can conclude that it means that you did not take a beach vacation in Los Cabos, Mexico or went to attend a family wedding.  My advice will be consult with a lawyer what to do if you did leave the US.