树剖板子那题，

#include<bits/stdc++.h>
using namespace std;
#define mkp make_pair
#define pb push_back
#define ls (rt << 1)
#define rs (rt << 1 | 1)
typedef long long ll;
const int N = 30010, inf = 0x3f3f3f3f;
int n, tim, fat[N], sz[N], son[N], dep[N], w[N], dfn[N], top[N], id[N]; 
int e, to[N << 1], nxt[N << 1], hd[N];
struct node{
	int mx, sum;
	node operator + (const node x) const {
		return (node){max(mx, x.mx), sum + x.sum};
	}
}tr[N << 1]; 
void add(int a, int b){
	to[++e] = b; nxt[e] = hd[a]; hd[a] = e;
}
void dfs(int u, int fa){
	fat[u] = fa; dep[u] = dep[fa] + 1;
	sz[u] = 1; son[u] = 0;
	for(int i = hd[u]; i; i = nxt[i]){
		int v = to[i]; if(v == fa) continue;
		dfs(v, u); sz[u] += sz[v];
		if(sz[v] > sz[son[u]]) son[u] = v; 
	}
	return;
}
void dfs2(int u, int topf){
	dfn[u] = ++tim; id[tim] = u;
	top[u] = topf;
	if(!son[u]) return;
	dfs2(son[u], topf);
	for(int i = hd[u]; i; i = nxt[i]){
		int v = to[i]; if(v == fat[u] || v == son[u]) continue;
		dfs2(v, v);
	}
	return;
}
void build(int rt, int l, int r){
	if(l == r)
		return tr[rt].mx = tr[rt].sum = w[id[l]], void();
	int mid = (l + r) >> 1;
	build(ls, l, mid);
	build(rs, mid + 1, r);
	tr[rt] = tr[ls] + tr[rs];
	return;
}
void update(int rt, int l, int r, int pos, int va){
	if(l == r)
		return tr[rt].mx = tr[rt].sum = va, void();
	int mid = (l + r) >> 1;
	if(pos <= mid) update(ls, l, mid, pos, va);
	else update(rs, mid + 1, r, pos, va);
	tr[rt] = tr[ls] + tr[rs];
	return;
} 
node query(int rt, int l, int r, int L, int R){
	if(L <= l && r <= R) return tr[rt];
	int mid = (l + r) >> 1;
	node ret = (node){-inf, 0};
	if(L <= mid) ret = ret + query(ls, l, mid, L, R);
	if(R > mid) ret = ret + query(rs, mid + 1, r, L, R);
	return ret;
}
node qrange(int x, int y){
	node ret = (node){-inf, 0};
	while(top[x] != top[y]){
		if(dep[top[x]] < dep[top[y]]) swap(x, y);
		ret = ret + query(1, 1, n, dfn[top[x]], dfn[x]);
		x = fat[top[x]];
	} 
	if(dep[x] > dep[y]) swap(x, y);
	ret = ret + query(1, 1, n, dfn[x], dfn[y]);
	return ret;
}
void updrange(int x, int y){
	update(1, 1, n, dfn[x], y);
} 
int main(){
	scanf("%d", &n);
	for(int i = 1, u, v; i < n; i++){
		scanf("%d%d", &u, &v);
		add(u, v); add(v, u); 
	}
	for(int i = 1; i <= n; i++)
		scanf("%d", &w[i]); 
	dfs(1, 0); dfs2(1, 1); 
	build(1, 1, n); 
	int m; scanf("%d", &m); 
	for(int i = 1, x, y; i <= m; i++){
		char ch[15]; scanf("%s%d%d", ch, &x, &y);
		if(ch[0] == 'C') updrange(x, y);
		else if(ch[1] == 'M') printf("%d\n", qrange(x, y).mx);
		else printf("%d\n", qrange(x, y).sum);
	} 
	return 0;
}