LCT模板（无讲解）

怎么说呢，照着打一遍就自然理解了，再打一遍就会背了，再打一遍就会推了。

 // luogu-judger-enable-o2
 #include<bits/stdc++.h>
 using namespace std;
 const int maxn=3E5+;
 int fa[maxn],son[maxn][],val[maxn],ans[maxn],n,m,opt,x,y,z;
 bool tag[maxn];
 bool notroot(int x){return son[fa[x]][]==x||son[fa[x]][]==x;}
 void update(int x){ans[x]=ans[son[x][]]^ans[son[x][]]^val[x];}
 void pushr(int x)
 {
     swap(son[x][],son[x][]);
     tag[x]^=;
 }
 void pushdown(int x)
 {
     if(tag[x])
     {
         if(son[x][])pushr(son[x][]);
         if(son[x][])pushr(son[x][]);
         tag[x]=;
     }
 }
 void rotate(int x,int c)
 {
     int y=fa[x];
     fa[x]=fa[y];
     son[y][!c]=son[x][c];
     if(son[x][c])fa[son[x][c]]=y;
     if(notroot(y)&&son[fa[y]][]==y)son[fa[y]][]=x;
     else if(notroot(y))son[fa[y]][]=x;
     son[x][c]=y;
     fa[y]=x;
     update(y);
     update(x);
 }
 void down(int x)
 {
     if(!notroot(x)){pushdown(x);return;}
     down(fa[x]);
     pushdown(x);
 }
 void splay(int x)
 {
     down(x);
     while(true)
     {
         int y=fa[x];
         if(!notroot(x))break;
         if(!notroot(y))
         {
             if(son[y][]==x)rotate(x,);
             else rotate(x,);
             break;
         }
         if(son[fa[y]][]==y)
         {
             if(son[y][]==x)rotate(y,),rotate(x,);
             else rotate(x,),rotate(x,);
         }
         else
         {
             if(son[y][]==x)rotate(y,),rotate(x,);
             else rotate(x,),rotate(x,);
         }
     }
 }
 void access(int x)
 {
     for(int y=;x;y=x,x=fa[x])
         splay(x),son[x][]=y,update(x);
 }
 void makeroot(int x)
 {
     access(x);
     splay(x);
     pushr(x);
 }
 int findroot(int x)
 {
     access(x);
     splay(x);
     while(son[x][])pushdown(x),x=son[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)fa[x]=y;
 }
 void cut(int x,int y)
 {
     makeroot(x);
     if(findroot(y)==x&&fa[y]==x&&!son[y][])
     {
         fa[y]=son[x][]=;
         update(x);
         update(y);
     }
 }
 int main()
 {
     ios::sync_with_stdio(false);
     cin>>n>>m;
     for(int i=;i<=n;++i)cin>>val[i];
     while(m--)
     {
         cin>>opt>>x>>y;
         if(opt==)
         {
             split(x,y);
             cout<<ans[y]<<endl;
         }
         else if(opt==)link(x,y);
         else if(opt==)cut(x,y);
         else
         {
             splay(x);
             val[x]=y;
         }
     }
     return ;
 }