动态树LCT

 #include<iostream>
 #include<cstdio>
 #include<cmath>
 #include<algorithm>
 using namespace std;
 const int maxn=+,INF=-1u>>;
 int v[maxn],maxv[maxn],minv[maxn],sumv[maxn],ch[maxn][],pre[maxn],top[maxn],flip[maxn],n,Q;
 inline int read(){
     int x=,sig=;char ch=getchar();
     while(!isdigit(ch)){if(ch=='-') sig=-;ch=getchar();}
     while(isdigit(ch)) x=*x+ch-'',ch=getchar();
     return x*=sig;
 }
 inline void write(int x){
     if(x==){putchar('');return;}if(x<) putchar('-'),x=-x;
     int len=,buf[];while(x) buf[len++]=x%,x/=;
     for(int i=len-;i>=;i--) putchar(buf[i]+'');return;
 }
 void maintain(int o){
     int lc=ch[o][],rc=ch[o][];
     maxv[o]=max(maxv[lc],maxv[rc]);
     minv[o]=min(minv[lc],minv[rc]);
     sumv[o]=sumv[lc]+sumv[rc];
     if(v[o]){
         sumv[o]+=v[o];
         maxv[o]=max(maxv[o],v[o]);
         minv[o]=min(minv[o],v[o]);
     } return;
 }
 void pushdown(int o){
     if(flip[o]){
         flip[ch[o][]]^=;
         flip[ch[o][]]^=;
         swap(ch[o][],ch[o][]);
         flip[o]=;
     } return;
 }
 void rotate(int x,int d){
     pushdown(x);
     int y=pre[x],z=pre[y];
     ch[y][d^]=ch[x][d];pre[ch[x][d]]=y;
     ch[z][ch[z][]==y]=x;pre[x]=z;
     ch[x][d]=y;pre[y]=x;
     maintain(y);return;
 }
 void splay(int x){
     int rt=x;
     while(pre[rt]) rt=pre[rt];
     if(x!=rt){
         top[x]=top[rt];top[rt]=;
         while(pre[x]){
             pushdown(pre[x]);
             rotate(x,ch[pre[x]][]==x);
         } maintain(x);
     } else pushdown(x);
     return;
 }
 void access(int x){
     int y=;
     while(x){
         splay(x);
         top[ch[x][]]=x;pre[ch[x][]]=;
         ch[x][]=y;
         top[y]=;pre[y]=x;
         maintain(x);
         y=x;x=top[x];
     } return;
 }
 void makeroot(int x){
     access(x);splay(x);flip[x]^=;return;
 }
 void link(int u,int v){
     makeroot(u);top[u]=v;return;
 }
 void query(int x,int y){
     if(x==y){
         puts("error");return;
     }
     makeroot(x);access(y);splay(y);
     write(maxv[y]);putchar(' ');write(minv[y]);putchar(' ');write(sumv[y]);putchar('\n');
     return;
 }
 void update(int pos,int cv){
     splay(pos);v[pos]=cv;
     maintain(pos);return;
 }
 void init(){
     maxv[]=-INF;minv[]=INF;sumv[]=;
     n=read();
     for(int i=;i<n;i++){
         int a=read(),b=read(),c=read();
         v[i+n]=c;
         link(a,i+n);link(i+n,b);
     }
     Q=read();
     while(Q--)
     {
         int tp=read(),a=read(),b=read();
         if(tp) query(a,b);
         else update(a+n,b);
     }
     return ;
 }
 int main(){init();return ;}