洛谷P3690 Link Cut Tree (动态树)

干脆整个LCT模板吧。

缺个链上修改和子树操作，链上修改的话join(u,v)然后把v splay到树根再打个标记就好。

至于子树操作...以后有空的话再学(咕咕咕警告)

 #include<bits/stdc++.h>
 using namespace std;
 typedef long long ll;
 const int N=1e5+;
 int n,m,a[N],Xor[N],fa[N],ch[N][],flp[N],sta[N],tp;
 #define l(u) ch[u][0]
 #define r(u) ch[u][1]
 void rev(int u) {flp[u]^=,swap(l(u),r(u));}
 void pu(int u) {Xor[u]=Xor[l(u)]^a[u]^Xor[r(u)];}
 void pd(int u) {if(flp[u])rev(l(u)),rev(r(u)),flp[u]=;}
 int sf(int u) {return u==r(fa[u]);}
 bool isrt(int u) {return u!=l(fa[u])&&u!=r(fa[u]);}
 void rot(int u) {
     int v=fa[u],f=sf(u);
     if(!isrt(v))ch[fa[v]][sf(v)]=u;
     ch[v][f]=ch[u][f^],fa[ch[v][f]]=v;
     fa[u]=fa[v],ch[u][f^]=v,fa[v]=u,pu(v);
 }
 void splay(int u) {
     sta[tp=]=u;
     for(int v=u; !isrt(v); v=fa[v])sta[++tp]=fa[v];
     for(; ~tp; pd(sta[tp--]));
     for(; !isrt(u); rot(u))if(!isrt(fa[u])&&sf(fa[u])==sf(u))rot(fa[u]);
     pu(u);
 }
 void access(int u) {for(int v=; u; splay(u),r(u)=v,pu(u),u=fa[v=u]);}
 void makert(int u) {access(u),splay(u),rev(u);}
 void join(int u,int v) {makert(u),access(v),splay(v);}
 int findrt(int u) {access(u),splay(u); for(; l(u); pd(u),u=l(u)); splay(u); return u;}
 void link(int u,int v) {makert(u); if(findrt(v)==u)return; fa[u]=v;}
 void cut(int u,int v) {join(u,v); if(l(v)!=u||r(u))return; fa[u]=l(v)=;}
 void upd(int u,int x) {makert(u),a[u]=x;}
 int qry(int u,int v) {join(u,v); return Xor[v];}
 int main() {
     scanf("%d%d",&n,&m);
     for(int i=; i<=n; ++i)scanf("%d",&a[i]);
     while(m--) {
         int f,x,y;
         scanf("%d%d%d",&f,&x,&y);
         if(f==)printf("%d\n",qry(x,y));
         else if(f==)link(x,y);
         else if(f==)cut(x,y);
         else if(f==)upd(x,y);
     }
     return ;
 }