bzoj 4034: [HAOI2015]树上操作——树链剖分

#include<cstdio>
#include<cstring>
#include<algorithm>
#define LL long long
const int M=150007;
int read(){
    int ans=0,f=1,c=getchar();
    while(c<‘0‘||c>‘9‘){if(c==‘-‘) f=-1; c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){ans=ans*10+(c-‘0‘); c=getchar();}
    return ans*f;
}
int max(int x,int y){return x>y?x:y;}
int n,m;
int first[M],cnt=1;
struct node{int to,next;}e[2*M];
void ins(int a,int b){e[++cnt]=(node){b,first[a]}; first[a]=cnt;}
void insert(int a,int b){ins(a,b); ins(b,a);}
int top[M],sz[M],son[M],mx[M],fa[M],id[M],idp=1;
void f1(int x){
    sz[x]=1;
    for(int i=first[x];i;i=e[i].next){
        int now=e[i].to;
        if(now==fa[x]) continue;
        fa[now]=x; f1(now);
        sz[x]+=sz[now]; 
        if(sz[now]>sz[son[x]]) son[x]=now;
    }
}
void f2(int x,int tp){
    top[x]=tp; mx[x]=id[x]=idp++;
    if(son[x]) f2(son[x],tp),mx[x]=max(mx[x],mx[son[x]]);
    for(int i=first[x];i;i=e[i].next){
        int now=e[i].to;
        if(now!=fa[x]&&now!=son[x]) f2(now,now),mx[x]=max(mx[x],mx[now]);
    }
}
struct pos{int l,r; LL sum,tag;}tr[4*M];
void build(int x,int l,int r){
    tr[x].l=l; tr[x].r=r;
    if(l==r) return ;
    int mid=(l+r)>>1;
    build(x<<1,l,mid);
    build(x<<1^1,mid+1,r);
}
void up(int x){tr[x].sum=tr[x<<1].sum+tr[x<<1^1].sum;}
void down(int x){
    if(tr[x].tag){
        int ls=x<<1,rs=x<<1^1;
        LL v=tr[x].tag;
        tr[x].tag=0; tr[ls].tag+=v; tr[rs].tag+=v;
        tr[ls].sum+=1LL*(tr[ls].r-tr[ls].l+1)*v;
        tr[rs].sum+=1LL*(tr[rs].r-tr[rs].l+1)*v;
    }
}
void modify(int x,int L,int R,LL s){
    if(L<=tr[x].l&&tr[x].r<=R){tr[x].tag+=s; tr[x].sum+=(tr[x].r-tr[x].l+1)*s; return ;}
    down(x);
    int mid=(tr[x].l+tr[x].r)>>1;
    if(L<=mid) modify(x<<1,L,R,s);
    if(R>mid) modify(x<<1^1,L,R,s);
    up(x);
}
LL v[M];
LL push_sum(int x,int L,int R){
    if(L<=tr[x].l&&tr[x].r<=R) return tr[x].sum;
    down(x);
    int mid=(tr[x].l+tr[x].r)>>1;
    LL ans=0;
    if(L<=mid) ans+=push_sum(x<<1,L,R);
    if(R>mid)  ans+=push_sum(x<<1^1,L,R);
    return ans;
}
LL qsum(int x){
    LL sum=0;
    while(top[x]!=top[1]){
        sum+=push_sum(1,id[top[x]],id[x]);
        x=fa[top[x]];
    }
    sum+=push_sum(1,id[1],id[x]);
    return sum;
}
int main(){
    int k,x,y;
    n=read(); m=read();
    for(int i=1;i<=n;i++) v[i]=read();
    for(int i=1;i<n;i++) x=read(),y=read(),insert(x,y);
    build(1,1,n); f1(1); f2(1,1);
    for(int i=1;i<=n;i++) modify(1,id[i],id[i],v[i]);
    for(int i=1;i<=m;i++){
        k=read();
        if(k==1) x=read(),y=read(),modify(1,id[x],id[x],y);
        else if(k==2) x=read(),y=read(),modify(1,id[x],mx[x],y);
        else x=read(),printf("%lld\n",qsum(x));
    }
    return 0;
}