【UER #1】DZY Loves Graph（待卡常数）

题解：

正解是可持久化并查集

但这个显然是lct可以维护的

但这常数是个问题啊？？？

#include <bits/stdc++.h>
using namespace std;
struct re{
  int a,b,c;
};
const int N=5e5;
int fa[N],ls[N],rs[N],v[N];
int cnt,last,last1,last2,n,m,ans;
bool rev[N];
deque<re> q1,q2;
void down(int x)
{
  if (!rev[x]) return;
  swap(ls[x],rs[x]);
  rev[ls[x]]^=1; rev[rs[x]]^=1;
  rev[x]=0;
}
bool pd(int x)
{
  if (ls[fa[x]]!=x&&rs[fa[x]]!=x) return(0);
  else return (1);
}
void rotate(int x,int y)
{
  int fath=fa[x];
  if (y==1)
  {
    rs[fath]=ls[x];
    if (ls[x]) fa[ls[x]]=fath;
  } else
  {
    ls[fath]=rs[x];
    if (rs[x]) fa[rs[x]]=fath;
  }
  fa[x]=fa[fath];
  if (pd(fath))
  {
    if (ls[fa[x]]==fath) ls[fa[x]]=x;
    else rs[fa[x]]=x;
  }
  fa[fath]=x;
  if (y==1) ls[x]=fath; else rs[x]=fath;
}
void dfs(int x)
{
  if (pd(x)) dfs(fa[x]);
  down(x); 
}
void splay(int x)
{
  dfs(x);
  int fath=fa[x];
  while (pd(x))
  {
    if (!pd(fa[x]))
    {
      if (x==ls[fa[x]]) rotate(x,2);
      else rotate(x,1);
    } else
    {
      if (ls[fa[fath]]==fath)
        if (ls[fath]==x) rotate(fath,2),rotate(x,2);
        else rotate(x,1),rotate(x,2);
      else if (rs[fath]==x) rotate(fath,1),rotate(x,1);
        else rotate(x,2),rotate(x,1);
    }
    fath=fa[x];
  }
}
void access(int x)
{
  for (int y=0;x;y=x,x=fa[x])
  {
    splay(x); rs[x]=y;
  }
}
void makeroot(int x)
{
  access(x);
  splay(x);
  rev[x]^=1;
}
int findroot(int x)
{
  access(x);
  splay(x);
  while (ls[x]) x=ls[x];
  return x;
}
bool find (int x,int y)
{
  makeroot(x);
  if (findroot(y)==x) return 1;
  else return 0;
}
void link(int x,int y)
{
  //**
  //cout<<x<<" "<<y<<endl;
  //**
  makeroot(x);
  fa[x]=y;
}
void cut(int x,int y)
{
  makeroot(x);
  access(y);
  splay(y);
  ls[y]=fa[x]=0;
}
char c[100];
int main()
{
   freopen("noip.in","r",stdin);
   freopen("noip.out","w",stdout);
   std::ios::sync_with_stdio(false);
   cin>>n>>m;
   for (int i=1;i<=m;i++)
   {
     cin>>c;int x,y;
     if (c[0]=='A')
     {
         cin>>x>>y;
         re a; a.a=x; a.b=y; a.c=i; q1.push_back(a);
         if (!find(x,y))
         {
           cnt++; ans+=i;
           link(x,i+n);
           link(i+n,y);
           v[i+n]=i;
         }
         last=1; last1=x; last2=y;
     }
     if (c[0]=='D')
     {
       last=2;
       cin>>x; q2.clear();
       for (int i=1;i<=x;i++)
       {
         re y=q1.back(); q1.pop_back(); q2.push_back(y);
         if (find(y.a,y.c+n))
         {
           cut(y.a,y.c+n); cut(y.b,y.c+n);
           cnt--; ans-=y.c;
         }
       }
     }
     if (c[0]=='R')
     {
       if (last==1)
       {
          if (find(last1,i-1+n))
          {
            cut(last1,i-1+n); cut(last2,i-1+n);
            cnt--; ans-=i-1;
          }
          q1.pop_back();
       } else
       {
          while (!q2.empty())
          {
            re x=q2.back(); q2.pop_back();
            q1.push_back(x);
            if (!find(x.a,x.b))
            {
              cnt++; ans+=x.c;
              link(x.a,x.c+n);
              link(x.b,x.c+n);
            }
          }
       }
     }
     if (cnt==n-1) cout<<ans; else cout<<0;
     cout<<endl;
   }
   return 0;
}