模板—LCT

#include<iostream>
#include<cstring>
#include<cstdio>
#define LL long long
using namespace std;
int f[100000],c[100000][2],st[100000];
bool r[100000];
#define l(x) c[x][0]
#define r(x) c[x][1]
inline bool nroot(int x){return c[f[x]][0]==x||c[f[x]][1]==x;}
void pushup(int x){;}
void pushr(int x){int t=l(x);l(x)=r(x);r(x)=t;r[x]^=1;}
void pushdown(int x)
{    
    if(!r[x])return;
    if(l(x))pushr(l(x));
    if(r(x))pushr(r(x));
    r[x]=0;
}
void rotate(int x)//
{
    int y=f[x],z=f[y],k=r(y)==x,w=c[x][!k];    
    if(nroot(y))c[z][r(z)==y]=x;c[x][!k]=y;c[y][k]=w;
    if(w)f[w]=y;f[y]=x;f[x]=z;
    pushup(y);
}
void splay(int x)//
{
    int y=x,z=0;st[++z]=y;
    while(nroot(y))st[++z]=y=f[y];
    while(z)pushdown(st[z--]);
    while(nroot(x))
    {
        y=f[x];z=f[y];
        if(nroot(y))rotate((l(y)==x)^(l(z)==y)?x:y);
        rotate(x);
    }
    pushup(x);
}
void access(int x){for(int y=0;x;x=f[y=x])splay(x),r(x)=y,pushup(x);}//
void makeroot(int x){access(x);splay(x);pushr(x);}//
int findroot(int x){access(x);splay(x);while(l(x))pushdown(x),x=l(x);splay(x);return x;}//
void split(int x,int y){makeroot(x);access(y);splay(y);}//
void link(int x,int y){makeroot(x);if(findroot(y)!=x)f[x]=y;}//
void cut(int x,int y)
{
    makeroot(x);
    if(findroot(y)==x&&f[y]==x&&!l(y))
    f[y]=r(x)=0,pushup(x);
}
int n,m;
signed main()
{    
    cin>>n>>m;
    char opt[10];int u,v;
    for(int i=1;i<=m;i++)
    {    
        cin>>opt;
        if(opt[0]=='C')cin>>u>>v,link(u,v);
        if(opt[0]=='D')cin>>u>>v,cut(u,v);
        if(opt[0]=='Q')
        {
            cin>>u>>v;
            if(findroot(u)==findroot(v))puts("Yes");
            else puts("No");
        }
    }
}