Qtree4

#欢迎提供更强的数据，本题目支持无限加数据（可私信，百度网盘地址） #数据范围和spoj略有不同

给出一棵边带权的节点数量为n的树，初始树上所有节点都是白色。有两种操作： C x，改变节点x的颜色，即白变黑，黑变白 A，询问树中最远的两个白色节点的距离，这两个白色节点可以重合(此时距离为0)。

In the first line there is an integer N (N <= 100000) In the next N-1 lines, the i-th line describes the i-th edge: a line with three integers a b c denotes an edge between a, b of value c (-1000 <= c <= 1000) In the next line, there is an integer Q denotes the number of instructions (Q <= 200000) In the next Q lines, each line contains an instruction "C a" or "A"

For each "A" operation, write one integer representing its result. If there is no white node in the tree, you should write "They have disappeared.".

3
1 2 1
1 3 1
7
A
C 1
A
C 2
A
C 3
A

2
2
0
They have disappeared.