D – How Many Answers Are Wrong （思维+带权并查集）
TT and FF are … friends. Uh… very very …
L – Connections in Galaxy War （逆序并查集）
In order to strengthen the defense ability, many s …
N – Is It A Tree? （有向图判树/判环）
A tree is a well-known data structure that is eith …
M – 小希的迷宫（无向图判树）
上次Gardon的迷宫城堡小希玩了很久（见Problem B），现在她也想设计一个迷宫让Gardon …
C – How Many Tables
Today is Ignatius’ birthday. He invites a lo …
B – The Suspects （简单并查集）
Severe acute respiratory syndrome (SARS), an atypi …
A – Wireless Network
An earthquake takes place in Southeast Asia. The A …
并查集
直接拿了之前简书的链接… https://www.jianshu.com/writer# …