动态树LCT

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
const int maxn=100000+10,INF=-1u>>1;
int v[maxn],maxv[maxn],minv[maxn],sumv[maxn],ch[maxn][2],pre[maxn],top[maxn],flip[maxn],n,Q;
inline int read(){
    int x=0,sig=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-') sig=-1;ch=getchar();}
    while(isdigit(ch)) x=10*x+ch-'0',ch=getchar();
    return x*=sig;
}
inline void write(int x){
    if(x==0){putchar('0');return;}if(x<0) putchar('-'),x=-x;
    int len=0,buf[15];while(x) buf[len++]=x%10,x/=10;
    for(int i=len-1;i>=0;i--) putchar(buf[i]+'0');return;
}
void maintain(int o){
    int lc=ch[o][0],rc=ch[o][1];
    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][0]]^=1;
        flip[ch[o][1]]^=1;
        swap(ch[o][0],ch[o][1]);
        flip[o]=0;
    } return;
}
void rotate(int x,int d){
    pushdown(x);
    int y=pre[x],z=pre[y];
    ch[y][d^1]=ch[x][d];pre[ch[x][d]]=y;
    ch[z][ch[z][1]==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]=0;
        while(pre[x]){
            pushdown(pre[x]);
            rotate(x,ch[pre[x]][0]==x);
        } maintain(x);
    } else pushdown(x);
    return;
}
void access(int x){
    int y=0;
    while(x){
        splay(x);
        top[ch[x][1]]=x;pre[ch[x][1]]=0;
        ch[x][1]=y;
        top[y]=0;pre[y]=x;
        maintain(x);
        y=x;x=top[x];
    } return;
}
void makeroot(int x){
    access(x);splay(x);flip[x]^=1;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('
');
    return;
}
void update(int pos,int cv){
    splay(pos);v[pos]=cv;
    maintain(pos);return;
}
void init(){
    maxv[0]=-INF;minv[0]=INF;sumv[0]=0;
    n=read();
    for(int i=1;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 0;}