魔法树[树剖]

​​传送门​​

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题意: 链修改,子树和查询

直接树剖就好了

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#include<bits/stdc++.h>
#include<cstdio>
#define N 100005
#define M 200005
#define ll long long
using namespace std;
int first[N],next[M],to[M],tot;
int sign,siz[N],son[N];
int n,m,dep[N],id[N],top[N],fa[N];
struct Node{ll val,tag;}t[N<<2]; 
int read(){
  int cnt=0,f=1;char ch=0;
  while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
  while(isdigit(ch))cnt=cnt*10+(ch-'0'),ch=getchar();
  return cnt*f;
}
/*--------------------------------dfs-----------------------------------*/
void add(int x,int y){
  next[++tot]=first[x],first[x]=tot,to[tot]=y;
}
void dfs1(int u,int f){
  siz[u]=1;
  for(int i=first[u];i;i=next[i]){
    int t=to[i]; if(t==f) continue;
    dep[t]=dep[u]+1 , fa[t]=u;
    dfs1(t,u); siz[u] += siz[t];
    if(siz[son[u]]<siz[t]) son[u]=t;
  }
}
void dfs2(int u,int Top){
  id[u]=++sign , top[u]=Top;
  if(son[u]) dfs2(son[u],Top);
  for(int i=first[u];i;i=next[i]){
    int t=to[i]; if(t==fa[u]||t==son[u]) continue;
    dfs2(t,t);
  }
}
/*-----------------------------------线段树-------------------------------------*/
void Pushdown(int x,int l,int r){
  if(t[x].tag){
    int mid=(l+r)>>1;
    t[x<<1].val += (ll)(mid-l+1) * t[x].tag;
    t[x<<1].tag += t[x].tag;
    t[x<<1|1].val += (ll)(r-mid) * t[x].tag;
    t[x<<1|1].tag +=t[x].tag;
    t[x].tag=0;
  }
}
void Pushup(int x){
  t[x].val = t[x<<1].val + t[x<<1|1].val;
}
void update(int x,int L,int R,int val,int l,int r){
  if(L<=l && r<=R){
    t[x].val += (ll)(r-l+1) * val;
    t[x].tag += val; return;
  } 
  Pushdown(x,l,r);
  int mid=(l+r)>>1;
  if(L<=mid) update(x<<1,L,R,val,l,mid);
  if(R>mid) update(x<<1|1,L,R,val,mid+1,r);
  Pushup(x);
}
ll quary(int x,int L,int R,int l,int r){
  if(L<=l && r<=R) return t[x].val;
  Pushdown(x,l,r);
  int mid=(l+r)>>1; ll ans=0;
  if(L<=mid) ans+=quary(x<<1,L,R,l,mid);
  if(R>mid) ans+=quary(x<<1|1,L,R,mid+1,r);
  return ans;
}
/*----------------------------------树剖-------------------------------------*/
void Update(int x,int y,int val){
  while(top[x]!=top[y]){
    if(dep[top[x]]<dep[top[y]]) swap(x,y);
    update(1,id[top[x]],id[x],val,1,n);
    x=fa[top[x]];
  }
  if(dep[x]<dep[y]) swap(x,y);
  update(1,id[y],id[x],val,1,n);
}
int main(){
  n=read();
  for(int i=1;i<n;i++){
    int x=read()+1,y=read()+1;
    add(x,y),add(y,x);
  }
  dep[1]=1 , dfs1(1,0) , dfs2(1,1);
  m=read(); char s[3];
  while(m--){
    scanf("%s",s);
    if(s[0]=='A'){
      int u=read()+1,v=read()+1,d=read();
      Update(u,v,d);
    }
    if(s[0]=='Q'){
      int x=read()+1;
      printf("%lld\n",quary(1,id[x],id[x]+siz[x]-1,1,n));
    }
  }return 0;
}