题目

#include <cstdio>
#include <iostream>
#include <algorithm>
using namespace std;
const int MAXN=31000;
int f[MAXN],min1;
int front[MAXN],behind[MAXN];
int find(int x)
{
    if(f[x]==x) return x;

    int fx=find(f[x]);

    front[x]+=front[f[x]];

    return f[x]=fx;
}
int main()
{
    int t;

    cin>>t;

    for(int i=1;i<=30000;i++)
     {
        f[i]=i;
        behind[i]=1;
     }
    for(int i=1;i<=t;i++)
    {
        int x,y;
        char c1[10];

         scanf("%s%d%d",c1,&x,&y);

        if(c1[0]=='M')
        {
            int fx=find(x);
            int fy=find(y);

            front[fx]=behind[fy];
            behind[fy]+=behind[fx];

            f[fx]=fy;
        }
        else
        {
            int ans=-1;
            int fx=find(x);
            int fy=find(y);

            if(fx==fy) ans=abs(front[x]-front[y])-1;
            printf("%d\n",ans);
        } 
    }

    return 0;
}