样例过，交上去爆零

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
#define ll long long
#define ls(x) x<<1
#define rs(x) x<<1|1
int n,q,cnt;
int u,v,d;
char ch;
vector<int>G[N];
int dep[N],fa[N],sz[N],top[N],rnk[N],dfn[N],son[N];
int siz[N];
ll w[N<<2],lzy[N<<2];
void dfs1(int u,int father){
	dep[u]=dep[father]+1;
	fa[u]=father;
	sz[u]=1;
	for(auto v:G[u]){
		if(v==father){
			continue;
		}
		dfs1(v,u);
		sz[u]+=sz[v];
		if(sz[v]>sz[son[u]]){
			son[u]=v;
		}
	}
}
void dfs2(int u,int tp){
	top[u]=tp,dfn[u]=++cnt;
	rnk[dfn[u]]=u;
	if(son[u]==0){
		return;
	}
	dfs2(son[u],tp);
	for(auto v:G[u]){
		if(v!=fa[u]&&v!=son[u]){
			dfs2(v,v);
		}
	}
}
void pushup(int u){
	w[u]=w[ls(u)]+w[rs(u)];
}
void build(int u,int l,int r){
	siz[u]=r-l+1;
	if(l==r){
		return;
	}
	int mid=l+r>>1;
	build(ls(u),l,mid);
	build(rs(u),mid+1,r);
	pushup(u);
}
void pushdown(int u){
	if(lzy[u]){
		lzy[ls(u)]+=lzy[u];
		lzy[rs(u)]+=lzy[u];
		w[ls(u)]+=siz[ls(u)]*lzy[u];
		w[rs(u)]+=siz[rs(u)]*lzy[u];
		lzy[u]=0;
	}
}
void update(int u,int l,int r,int L,int R,int p){
	if(L<=l&&r<=R){
		w[u]+=siz[u]*p;
		lzy[u]+=p;
	}
	else if(!(R<l||r<L)){
		pushdown(u);
		int mid=l+r>>1;
		update(ls(u),l,mid,L,R,p);
		update(rs(u),mid+1,r,L,R,p);
		pushup(u);
	}
}
void modify(int x,int y,int z){
	while(top[x]!=top[y]){
		if(dep[top[x]]<dep[top[y]]){
			swap(x,y);
		}
		update(1,1,n,dfn[top[x]],dfn[x],z);
		x=fa[top[x]];
	}
	if(dfn[x]>dfn[y]){
		swap(x,y);
	}
	update(1,1,n,dfn[x],dfn[y],z);
}
ll qry(int u,int l,int r,int L,int R){
	if(L<=l&&r<=R){
		return w[u];
	}
	else if(!(R<l||r<L)){
		pushdown(u);
		int mid=l+r>>1;
		return qry(ls(u),l,mid,L,R)+qry(rs(u),mid+1,r,L,R);
	}
return 0;
}
int main(){
	cin.tie(0)->sync_with_stdio(0);
	cin>>n;
	for(int i=1;i<n;i++){
		cin>>u>>v;
		u++,v++;
		G[u].push_back(v);
		G[v].push_back(u);
	}
	dfs1(1,0);
	dfs2(1,0);
	build(1,1,n);
	cin>>q;
	while(q--){
		cin>>ch;
		if(ch=='A'){
			cin>>u>>v>>d;
			u++,v++;
			modify(u,v,d);
		}
		else{
			cin>>u; u++;
			cout<<qry(1,1,n,dfn[u],dfn[u]+sz[u]-1)<<"\n";
		}
	}
return 0;
}