POJ 1988 Cube Stacking 并查集 + 权值（隐含）

Cube Stacking

Time Limit: 2000MS Memory Limit: 30000KTotal Submissions: 19072 Accepted: 6643Case Time Limit: 1000MS
Description
Farmer John and Betsy are playing a game with N (1 <= N <= 30,000)identical cubes labeled 1 through N. They start with N stacks, each containing a single cube. Farmer John asks Betsy to perform P (1<= P <= 100,000) operation. There are two types of operations: moves and counts. * In a move operation, Farmer John asks Bessie to move the stack containing cube X on top of the stack containing cube Y. * In a count operation, Farmer John asks Bessie to count the number of cubes on the stack with cube X that are under the cube X and report that value. Write a program that can verify the results of the game. 
Input
* Line 1: A single integer, P * Lines 2..P+1: Each of these lines describes a legal operation. Line 2 describes the first operation, etc. Each line begins with a 'M' for a move operation or a 'C' for a count operation. For move operations, the line also contains two integers: X and Y.For count operations, the line also contains a single integer: X. Note that the value for N does not appear in the input file. No move operation will request a move a stack onto itself. 
Output
Print the output from each of the count operations in the same order as the input file. 
Sample Input
6M 1 6C 1M 2 4M 2 6C 3C 4
Sample Output
102

题意 ：

此题　M 1 6 代表将含编号１的木块堆放到含编号６的木块堆上面，C 1 是问编号１的木块下面有多少木块。

难点在于如何维护每个非节点的木块的权值，由于一个个枚举会超时，效率低，所以用并查集，那该怎么办呢？

首先开一个数组cnt[x]记录父节点x下的木块块数（包括x自己），再开dis[y]记录y到x的距离(即y 与 x 之间的木块数)，则y下面的木块块数为cnt[x] - dis[y] - 1。