POJ1988 并查集的使用

Cube Stacking

Time Limit: 2000MS		Memory Limit: 30000K
Total Submissions: 21157		Accepted: 7395
Case 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

6
M 1 6
C 1
M 2 4
M 2 6
C 3
C 4

Sample Output

1
0
2

#include<stdio.h>
#define N 30001

int count[N], num[N], pre[N];

void inite()
{
    for(int i = 0; i < N; i++)
    {
        count[i] = 0;
        num[i] = 1;
        pre[i] = i;
    }
}

int find(int x)
{
    if(pre[x] == x)
        return x;

    int t = find(pre[x]);
    count[x] += count[pre[x]];
    pre[x] = t;
    return t;

}
void Union(int x, int y)
{
    int i = find(x);
    int j = find(y);
    if(i == j)
    {
        return;
    }
    count[i] = num[j];
    num[j] += num[i];
    pre[i] = j;
}



int main()
{
    int i, x, y, n;
    char s[2];
    scanf("%d",&n);
    inite();
    for(i = 0; i < n; i++)
    {
        scanf("%s",s);
        if(s[0] == 'M')
        {
            scanf("%d%d",&x,&y);
            Union(x,y);
        }
        else if(s[0] == 'C')
        {
            scanf("%d",&x);
            int c = find(x);
            printf("%d\n",count[x]);
        }
    }
    return 0;
}