system
A chat on subreddit /r/me_irl
human
After the USA left, the war continued and was won by the Viet Kong.

Also, a retreat is considered to be a "loss" in my books. So, yeah, they lost the war.
gpt
No, the Viet Cong were pretty much eliminated as a fighting force after the Tet Offensive in 1968.  The VC were irregular guerrilla fighters.  After the US left it was the regular North Vietnamese Army that conquered South Vietnam and it took them 2 more years to do it.