P1196 银河英雄传说

设置两个数组来记录后面的长度和前面的长度

#include<iostream>
#include<cstdio> 
#include<cstring>
#include<string>
#include<algorithm>
#include<queue>
#include<vector>
#include<cmath>
using namespace std;
int behind[30010],front[30010],f[30010];
int find(int x)
{
    if(f[x]==x) return x;
    int fx=find(f[x]);
    front[x]+=front[f[x]];
    return f[x]=fx;
}
void mix(int x,int y)
{
    int fx=find(x);
    int fy=find(y);
    front[fx]=behind[fy];
    behind[fy]+=behind[fx];
    f[fx]=fy;
}
int main()
{
    for(int i=1;i<=30000;i++)
    {
        f[i]=i;
        behind[i]=1;
        //front[i]=0;
    }
    int T;
    scanf("%d",&T);
    for(int i=1;i<=T;i++)
    {
        int x,y;
        char p;
        cin>>p;
        scanf("%d%d",&x,&y);
        if(p=='M')
          mix(x,y);
        else{
            if(find(x)!=find(y))
              printf("-1\n");
            else
            printf("%d\n",abs(front[y]-front[x])-1);//  \n回车 ！ 
        }
    }
    return 0;
}