luogu1196 [noi2002]galaxy银河英雄传说(带权并查集)

挺裸的带权并查集。。。注意一下N应该是300000，而不是30000

#include<cstdio>#include<cmath>#include<algorithm>#include<iostream>using namespace std;int const N=300005;int n,fa[N],size[N],s[N];//s[i] i前面有多少战舰inline int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();    return x*f;}inline int find(int x){    if(fa[x]==x) return x;    int xx=find(fa[x]);    s[x]+=s[fa[x]];    return fa[x]=xx;}int main(){//  freopen("a.in","r",stdin);    n=read();    for(int i=1;i<=n;++i) fa[i]=i,size[i]=1;     while(n--){        char ss[2];scanf("%s",ss);        int x=read(),y=read();        int xx=find(x),yy=find(y);        if(ss[0]=='M'){            fa[xx]=yy;s[xx]=size[yy];size[yy]+=size[xx];        }        if(ss[0]=='C'){            if(xx==yy) printf("%d\n",abs(s[x]-s[y])-1);            else puts("-1");        }    }    return 0;}