What are the "four-district hukou" and "Qingdao permanent hukou" in the recruitment of institutions in Qingdao, and is the collective hukou of colleges and universities one of them?

Permanent residence in Qingdao means that candidates should have permanent residence in seven districts and five cities in Qingdao (excluding college students' collective households); Qingdao's four-district hukou means that the applicant should have a permanent residence in the south, north, Sifang, Licang District, China-Korea police station, China-Korea border police station and Maidao police station of Qingdao (excluding college students' collective households); Not restricted by household registration means that people with China nationality are not restricted by household registration.