[CodeChef-ANUDTQ] Dynamic Trees and Queries

类似维护括号序列，给每个点建两个点，然后所有操作都能轻松支持了。注意sum和lastans是long long。

#include<cstdio>
#include<algorithm>
#define rep(i,l,r) for (int i=(l); i<=(r); i++)
#define For(i,x) for (int i=h[x],k; i; i=nxt[i])
typedef long long ll;
using namespace std;

const int N=400010;
ll ans,sm[N];
int n,nd,tim,rt,op,x,y,m,cnt,a[N],tag[N];
int v[N],f[N],L[N],R[N],sz[N],c[N][2],h[N],to[N],nxt[N];

void add(int u,int v){ to[++cnt]=v; nxt[cnt]=h[u]; h[u]=cnt; }

void dfs(int x,int fa){
    L[x]=++tim; v[tim]=a[x];
    For(i,x) if ((k=to[i])!=fa) dfs(k,x);
    R[x]=++tim; v[tim]=a[x];
}

void upd(int x){
    sm[x]=sm[c[x][0]]+sm[c[x][1]]+v[x];
    sz[x]=sz[c[x][0]]+sz[c[x][1]]+1;
}

void put(int x,int k){ v[x]+=k; sm[x]+=1ll*k*sz[x]; tag[x]+=k; }

void push(int x){
    if (!tag[x]) return;
    if (c[x][0]) put(c[x][0],tag[x]);
    if (c[x][1]) put(c[x][1],tag[x]);
    tag[x]=0;
}

void pd(int x){ if (f[x]) pd(f[x]); push(x); }

int build(int l,int r){
    int mid=(l+r)>>1,x=mid;
    if (l<mid) c[x][0]=build(l,mid-1),f[c[x][0]]=x;
    if (mid<r) c[x][1]=build(mid+1,r),f[c[x][1]]=x;
    upd(x); return x;
}

void rot(int &rt,int x){
    int y=f[x],z=f[y],w=c[y][1]==x;
    if (y==rt) rt=x; else c[z][c[z][1]==y]=x;
    f[x]=z; f[y]=x; f[c[x][w^1]]=y; c[y][w]=c[x][w^1];
    c[x][w^1]=y; upd(y);
}

void splay(int &rt,int x){
    for (pd(x); x!=rt; rot(rt,x)){
        int y=f[x],z=f[y];
        if (y!=rt) (c[z][0]==y)^(c[y][0]==x) ? rot(rt,x) : rot(rt,y);
    }
    upd(x);
}

int pre(int x){ splay(rt,x); for (x=c[x][0]; c[x][1]; x=c[x][1]); return x; }
int lst(int x){ splay(rt,x); for (x=c[x][1]; c[x][0]; x=c[x][0]); return x; }

void Ins(int x,int y){
    int k=lst(L[x]); splay(rt,L[x]); splay(c[rt][1],k);
    c[k][0]=++nd; v[nd]=y; f[nd]=k; R[++n]=nd;
    nd++; c[nd-1][0]=nd; v[nd]=y; f[nd]=nd-1; L[n]=nd;
    upd(nd); upd(nd-1); upd(k); upd(rt);
}

void Add(int x,int y){
    int l=pre(L[x]),r=lst(R[x]); splay(rt,l); splay(c[rt][1],r);
    put(c[r][0],y); upd(r); upd(rt);
}

void Del(int x){
    int l=pre(L[x]),r=lst(R[x]); splay(rt,l); splay(c[rt][1],r);
    c[r][0]=f[c[r][0]]=0; upd(r); upd(rt);
}

ll Que(int x){ int l=pre(L[x]),r=lst(R[x]); splay(rt,l); splay(c[rt][1],r); return sm[c[r][0]]; }

int main(){
    freopen("anudtq.in","r",stdin);
    freopen("anudtq.out","w",stdout);
    scanf("%d",&n);
    rep(i,1,n) scanf("%d",&a[i]);
    rep(i,2,n) scanf("%d%d",&x,&y),x++,y++,add(x,y),add(y,x);
    tim=1; dfs(1,0); rt=build(1,tim+1); nd=tim+1; scanf("%d",&m);
    rep(i,1,m){
        scanf("%d%d",&op,&x); x+=ans+1;
        if (op==1) scanf("%d",&y),Ins(x,y);
        if (op==2) scanf("%d",&y),Add(x,y);
        if (op==3) Del(x);
        if (op==4) printf("%lld
",ans=Que(x)/2);
    }
    return 0;
}