poj1988Cube Stacking（并查集+路径压缩）

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;

const int maxn=30001;
int p;

struct
{
int father,tot,dis;
}block[maxn];

void in()
{
for(int i=0;i<maxn;++i)
{
block[i].dis=0;
block[i].father=i;
block[i].tot=1;
}
}

int getanc(int a)
{

if(block[a].father==a) return a;

int ret;

ret=getanc(block[a].father);
block[a].dis+=block[block[a].father].dis;
block[a].father=ret;

return ret;
}

void union_set(int a,int b)
{
int aa=getanc(a);
int bb=getanc(b);
block[bb].dis=block[aa].tot;//b元素的代表元素到代表元素的距离
block[bb].father=aa;//b元素的代表元素父节点更新
block[aa].tot+=block[bb].tot;//元素总个数更新
}
void print(int a)
{
int aa=getanc(a);
printf("%d\n",block[aa].tot-block[a].dis-1); //代表元素总个数-当前元素到代表元素的距离-本身=其下元素个数
}
int main()
{
scanf("%d",&p);

char s;
int x,y;

in();

while(p--)
{
getchar();
scanf("%c",&s);
if(s=='M')
{
scanf("%d %d",&x,&y);
union_set(x,y);
}
else {scanf("%d",&x);print(x);}
}
return 0;
}