build那里d[id]应该是a[dfn[l]]吧
by Galex @ 2022-04-07 15:47:37
@[Land__ER](/user/546558) dfs2里面，应该先判id等于0吧，不然tot空加一次就寄了
或者写成`if(son[id]) dfs2(son[id],t);`
by StarLbright40 @ 2022-04-07 16:35:52