树剖模板题了，
Code
#include <cstdio>
#include <algorithm>
#define MID int mid=(l+r)>>1,ls=id<<1,rs=id<<1|1
#define N 30010
using namespace std;
struct node{int sum,mx;node(){sum=0,mx=-1e9;}}T[N*4];
struct info{int to,nex;}e[N*2];
int n,A[N],tot,head[N],tag[N*4];
int dep[N],fa[N],sz[N],son[N];
int cnt,tp[N],tw[N],tid[N];
inline int read(){
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
inline void Link(int u,int v){
e[++tot].nex=head[u];e[tot].to=v;head[u]=tot;
}
void update(int l,int r,int id,int p,int x){
if(l==r){T[id].sum=T[id].mx=x;return;}
MID;
if(p<=mid) update(l,mid,ls,p,x);
else update(mid+1,r,rs,p,x);
T[id].sum=T[ls].sum+T[rs].sum;
T[id].mx=max(T[ls].mx,T[rs].mx);
}
int querySum(int l,int r,int id,int L,int R){
if(L<=l&&r<=R) return T[id].sum;
MID;
int res=0;
if(L<=mid) res+=querySum(l,mid,ls,L,R);
if(R>mid) res+=querySum(mid+1,r,rs,L,R);
return res;
}
int queryMx(int l,int r,int id,int L,int R){
if(L<=l&&r<=R) return T[id].mx;
MID;
int res=-1e9;
if(L<=mid) res=max(res,queryMx(l,mid,ls,L,R));
if(R>mid) res=max(res,queryMx(mid+1,r,rs,L,R));
return res;
}
void dfs(int u,int pre){
sz[u]=1;
for(int i=head[u],mx=0;i;i=e[i].nex){
int v=e[i].to;
if(v==pre) continue;
dep[v]=dep[u]+1;
fa[v]=u;
dfs(v,u);
sz[u]+=sz[v];
if(sz[v]>mx) son[u]=v,mx=sz[v];
}
}
void dddfs(int u,int top){
tp[u]=top;
tid[u]=++cnt;
tw[cnt]=A[u];
if(!son[u]) return;
dddfs(son[u],top);
for(int i=head[u];i;i=e[i].nex){
int v=e[i].to;
if(v!=son[u]&&v!=fa[u]) dddfs(v,v);
}
}
inline int qRangeSum(int u,int v){
int res=0;
while(tp[u]!=tp[v]){
if(dep[tp[u]]<dep[tp[v]]) swap(u,v);
res+=querySum(1,n,1,tid[tp[u]],tid[u]);
u=fa[tp[u]];
}
if(dep[u]>dep[v]) swap(u,v);
res+=querySum(1,n,1,tid[u],tid[v]);
return res;
}
inline int qRangeMx(int u,int v){
int res=-1e9;
while(tp[u]!=tp[v]){
if(dep[tp[u]]<dep[tp[v]]) swap(u,v);
res=max(res,queryMx(1,n,1,tid[tp[u]],tid[u]));
u=fa[tp[u]];
}
if(dep[u]>dep[v]) swap(u,v);
res=max(res,queryMx(1,n,1,tid[u],tid[v]));
return res;
}
void build(int l,int r,int id){
if(l==r){
T[id].sum=T[id].mx=tw[l];
return;
}
MID;
build(l,mid,ls);
build(mid+1,r,rs);
T[id].sum=T[ls].sum+T[rs].sum;
T[id].mx=max(T[ls].mx,T[rs].mx);
}
inline void Init(){
n=read();
for(int i=1;i<n;++i){
int u=read(),v=read();
Link(u,v),Link(v,u);
}
for(int i=1;i<=n;A[i++]=read());
dfs(1,0);
dddfs(1,1);
build(1,n,1);
}
inline void solve(){
int m=read(),x,y;
char s[10];
while(m--){
scanf("%s%d%d\n",s,&x,&y);
if(s[1]=='H') update(1,n,1,tid[x],y);
else if(s[1]=='M') printf("%d\n",qRangeMx(x,y));
else printf("%d\n",qRangeSum(x,y));
}
}
int main(){Init();solve();}