【HDU】2818-Building Block（并查集）

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn = 30005;
int n,fa[maxn];
int num[maxn],Size[maxn];
char op[5];
int find_father(int u){
    if(fa[u] == u)
        return fa[u];
    else{
        int temp = fa[u];
        fa[u] = find_father(fa[u]);
        num[u] += num[temp];
        return fa[u];
    }
}
int main(){
    while(scanf("%d",&n) != EOF){
        for(int i = 0; i <= 30000; i++){
            fa[i]   = i;
            Size[i] = 1;
            num[i]  = 0;
        }
        int x,y;
        for(int i = 1; i <= n; i++){
            scanf("%s",op);
            if(op[0] == 'M'){
                scanf("%d%d",&x,&y);
                int fx = find_father(x),fy = find_father(y);
                if(fx!= fy){
                    fa[fx] = fy;
                    num[fx]  = Size[fy];
                    Size[fy]+= Size[fx];
                    Size[fx] = 0;
                }
            }
            else{
                scanf("%d",&x);
                find_father(x);
                printf("%d\n",num[x]);
            }
        }
    }
    return 0;
}