HU 7778 then HU 4321 at Beijing
Qionghai → Beijing → Haikou
Timetable, Beijing time
23:00HU 7778 from Qionghai at the gate
22:30HU 4321 to Haikou leaves the gate
23 h 30 apart on the timetable, overnight
HU 4321 leaves 23 h 30 after HU 7778 arrives on the timetable: more than half a day, so not a connection we count.