BZOJ 2836 魔法树

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxv 100500
#define maxe 200500
using namespace std;
long long n,q,x,y,z,g[maxv],nume=1,dis[maxv],top[maxv],fath[maxv],son[maxv],size[maxv],dfn[maxv],mx[maxv],times=0;
struct edge
{
    long long v,nxt;
}e[maxe];
long long ls[maxv<<2],rs[maxv<<2],val[maxv<<2],lazy[maxv<<2],sum[maxv<<2],tot=0,root;
char s[10];
void addedge(long long u,long long v)
{
    e[++nume].v=v;
    e[nume].nxt=g[u];
    g[u]=nume;
}
void dfs1(long long x)
{
    size[x]=1;son[x]=0;
    for (long long i=g[x];i;i=e[i].nxt)
    {
        long long v=e[i].v;
        if (v!=fath[x])
        {
            fath[v]=x;dis[v]=dis[x]+1;
            dfs1(v);
            size[x]+=size[v];
            if (size[son[x]]<size[v]) son[x]=v;
        }
    }
}
void dfs2(long long x,long long father)
{
    top[x]=father;dfn[x]=mx[x]=++times;
    if (son[x]) {dfs2(son[x],father);mx[x]=max(mx[x],mx[son[x]]);}
    for (long long i=g[x];i;i=e[i].nxt)
    {
        long long v=e[i].v;
        if ((v!=fath[x]) && (v!=son[x]))
        {
            dfs2(v,v);
            mx[x]=max(mx[x],mx[v]);
        }
    }
}
void build(long long &now,long long left,long long right)
{
    now=++tot;
    if (left==right) return;
    long long mid=(left+right)>>1;
    build(ls[now],left,mid);
    build(rs[now],mid+1,right);
}
void pushdown(long long now,long long left,long long right)
{
    if (!lazy[now]) return;
    long long mid=(left+right)>>1;
    lazy[ls[now]]+=lazy[now];sum[ls[now]]+=(mid-left+1)*lazy[now];
    lazy[rs[now]]+=lazy[now];sum[rs[now]]+=(right-mid)*lazy[now];
    lazy[now]=0;
}
void modify(long long now,long long left,long long right,long long l,long long r,long long val)
{
    pushdown(now,left,right);
    if ((left==l) && (right==r))
    {
        lazy[now]+=val;sum[now]+=(right-left+1)*val;
        return;
    }
    long long mid=(left+right)>>1;
    if (r<=mid) modify(ls[now],left,mid,l,r,val);
    else if (l>=mid+1) modify(rs[now],mid+1,right,l,r,val);
    else
    {
        modify(ls[now],left,mid,l,mid,val);
        modify(rs[now],mid+1,right,mid+1,r,val);
    }
    sum[now]=sum[ls[now]]+sum[rs[now]];
}
void add()
{
    long long f1=top[x],f2=top[y];
    while (f1!=f2)
    {
        if (dis[f1]<dis[f2]) {swap(f1,f2);swap(x,y);}
        modify(root,1,n,dfn[f1],dfn[x],z);
        x=fath[f1];f1=top[x];    
    }
    if (dis[x]>dis[y]) swap(x,y);
    modify(root,1,n,dfn[x],dfn[y],z);
}
long long query(long long now,long long left,long long right,long long l,long long r)
{
    pushdown(now,left,right);
    if ((left==l) && (right==r)) return sum[now];
    long long mid=(left+right)>>1;
    if (r<=mid) return query(ls[now],left,mid,l,r);
    else if (l>=mid+1) return query(rs[now],mid+1,right,l,r);
    else return query(ls[now],left,mid,l,mid)+query(rs[now],mid+1,right,mid+1,r);
}
void ask()
{
    printf("%lld\n",query(root,1,n,dfn[x],mx[x]));
}
int main()
{
    scanf("%lld",&n);
    for (long long i=1;i<=n-1;i++)
    {
        scanf("%lld%lld",&x,&y);x++;y++;
        addedge(x,y);addedge(y,x);
    }
    dfs1(1);
    dfs2(1,1);
    build(root,1,n);
    scanf("%lld",&q);
    for (long long i=1;i<=q;i++)
    {
        scanf("%s",s);
        if (s[0]==‘A‘)
        {
            scanf("%lld%lld%lld",&x,&y,&z);x++;y++;
            add();
        }
        else
        {
            scanf("%lld",&x);x++;
            ask();
        }
    }
    return 0;
}