RT。

数组应该没有锅。

#include<bits/stdc++.h>
#define ll long long
#define inf 1<<30
#define INF 1ll<<60
using namespace std;
const int MAXN=1e5+10;
struct node{
	int l,r;
	ll sum,inc;
}tr[MAXN<<2];
#define ls i<<1
#define rs i<<1|1
void pushup(int i){
	tr[i].sum=tr[ls].sum+tr[rs].sum;
}
void pushdown(int i){
	if(!tr[i].inc) return;
	tr[ls].sum+=tr[i].inc*(tr[ls].r-tr[ls].l+1);
	tr[rs].sum+=tr[i].inc*(tr[rs].r-tr[rs].l+1);
	tr[ls].inc+=tr[i].inc;
	tr[rs].inc+=tr[i].inc;
	tr[i].inc=0;
}
void build(int i,int l,int r){
	tr[i].l=l;tr[i].r=r;tr[i].inc=0;
	if(l==r){
		tr[i].sum=0;
		return;
	}int mid=l+r>>1;
	build(ls,l,mid);build(rs,mid+1,r);
	pushup(i);
}
void upd(int i,int l,int r,ll v){
	if(tr[i].l>=l&&tr[i].r<=r){
		tr[i].sum+=v*(r-l+1);
		tr[i].inc+=v;return;
	}pushdown(i);
	int mid=tr[i].l+tr[i].r>>1;
	if(r<=mid) upd(ls,l,r,v);
	else if(l>mid) upd(rs,l,r,v);
	else upd(ls,l,mid,v),upd(rs,mid+1,r,v);
	pushup(i);
}
ll query(int i,int l,int r){
	if(tr[i].l>=l&&tr[i].r<=r)
		return tr[i].sum;
	pushdown(i);
	int mid=tr[i].l+tr[i].r>>1;
	if(r<=mid) return query(ls,l,r);
	else if(l>mid) return query(rs,l,r);
	else return query(ls,l,mid)+query(rs,mid+1,r);
}

vector<int> e[MAXN];
int son[MAXN],fa[MAXN],dep[MAXN],siz[MAXN];
void predfs(int x,int f){
	son[x]=-1;fa[x]=f;
	siz[x]=1;
	for(int i=0;i<e[x].size();i++){
		int s=e[x][i];
		if(s==f) continue;
		dep[s]=dep[x]+1;
		predfs(s,x);
		siz[x]+=siz[s];
		if(son[x]==-1||siz[son[x]]<siz[s])
			son[x]=s;
	}
}
int top[MAXN],dfn[MAXN],lnk[MAXN],tot=0;
int ed[MAXN];
void dfs(int x,int tp){
	top[x]=tp;
	dfn[x]=++tot;
	lnk[tot]=x;
	if(son[x]==-1) return;
	dfs(son[x],tp);
	for(int i=0;i<e[x].size();i++){
		int s=e[x][i];
		if(s==fa[x]||s==son[x]) continue;
		dfs(s,s);
	}ed[x]=tot;
}
void cpu(int u,int v,ll x){
	while(top[u]!=top[v]){
		if(dep[top[u]]<dep[top[v]]) swap(u,v);
		upd(1,dfn[top[u]],dfn[u],x);
		u=fa[top[u]];
	}if(dfn[u]>dfn[v]) swap(u,v);
	upd(1,dfn[u],dfn[v],x);
}
int main()
{
	int n;
	scanf("%d",&n);
	for(int i=1,x,y;i<n;i++){
		scanf("%d%d",&x,&y);
		x++;y++;
		e[x].push_back(y);
		e[y].push_back(x);
	}
	predfs(1,0);
	dfs(1,1);
	build(1,1,n);
	int Q,u,v;char s;ll t;
	scanf("%d",&Q);
	while(Q--){
		s=getchar();
		while(s!='A'&&s!='Q')
			s=getchar();
		if(s=='A'){
			scanf("%d%d%lld",&u,&v,&t);
			u++;v++;
			cpu(u,v,t);
		}else{
			scanf("%d",&u);
			u++;
			printf("%lld\n",query(1,dfn[u],ed[u]));
		}
	}
}