还是树剖模板啊QwQ

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#define maxn 600100

using namespace std;

struct node
{
    long long max_num,sum;
};
node tree[maxn<<2];
int n,m;
long long num[maxn],num_rnk[maxn];
int dep[maxn],fa[maxn],son[maxn],siz[maxn],rnk[maxn],top[maxn],rnk_cnt;
long long tot,ans;
struct nn
{
    int ed,nxt;
};
nn edge[maxn<<1]; 
int cnt,first[maxn];

inline void add_edge(int s,int e)
{
    ++cnt;
    edge[cnt].ed=e;
    edge[cnt].nxt=first[s];
    first[s]=cnt;
    return;
}

inline void dfs_1(int now,int pre)
{
    fa[now]=pre; dep[now]=dep[pre]+1; siz[now]=1;
    for(register int i=first[now];i;i=edge[i].nxt)
    {
        int e=edge[i].ed;
        if(e==fa[now]) continue;
        dfs_1(e,now);
        siz[now]+=siz[e];
        if(son[now]==-1||siz[e]>siz[son[now]]) son[now]=e;
    }
    return;
}

inline void dfs_2(int now,int heavy_fa)
{
    ++rnk_cnt;
    rnk[now]=rnk_cnt; num_rnk[rnk_cnt]=num[now]; top[now]=heavy_fa;
    if(son[now]==-1) return;
    dfs_2(son[now],heavy_fa);
    for(register int i=first[now];i;i=edge[i].nxt)
    {
        int e=edge[i].ed;
        if(e!=fa[now]&&e!=son[now]) dfs_2(e,e);
    }
    return;
}

inline void build(int k,int l,int r)
{
    if(l==r)
    {
        tree[k].sum=num_rnk[l];
        tree[k].max_num=num_rnk[l];
        return;
    }
    int mid=(l+r)>>1,son=k<<1;
    build(son,l,mid); build(son|1,mid+1,r);
    tree[k].sum=tree[son].sum+tree[son|1].sum;
    tree[k].max_num=max(tree[son].max_num,tree[son|1].max_num);
    return;
}

inline void modify(int k,int l,int r,int x,int y,long long v)
{
    if(r<x||l>y) return;
    if(x<=l&&r<=y)
    {
        tree[k].sum=v;
        tree[k].max_num=v;
        return;
    }
    int mid=(l+r)>>1,son=k<<1;
    modify(son,l,mid,x,y,v); modify(son|1,mid+1,r,x,y,v);
    tree[k].sum=tree[son].sum+tree[son|1].sum;
    tree[k].max_num=max(tree[son].max_num,tree[son|1].max_num);
    return;
}

inline long long query(int k,int l,int r,int x,int y)
{
    if(r<x||l>y) return -1e18;
    if(x<=l&&r<=y) return tree[k].max_num;
    int mid=(l+r)>>1,son=k<<1;
    return max(query(son,l,mid,x,y),query(son|1,mid+1,r,x,y));
}

inline void tree_max(int x,int y)
{
    ans=-1e18;
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans=max(ans,query(1,1,n,rnk[top[x]],rnk[x]));
        x=fa[top[x]];
    }
    ans=max(ans,query(1,1,n,min(rnk[x],rnk[y]),max(rnk[x],rnk[y])));
    return;
}

inline void get_sum(int k,int l,int r,int x,int y)
{
    if(r<x||l>y) return;
    if(x<=l&&r<=y)
    {
        tot+=tree[k].sum;
        return;
    }
    int mid=(l+r)>>1,son=k<<1;
    get_sum(son,l,mid,x,y); get_sum(son|1,mid+1,r,x,y);
    return;
}

inline void tree_sum(int x,int y)
{
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        tot=0;
        get_sum(1,1,n,rnk[top[x]],rnk[x]);
        ans+=tot;
        x=fa[top[x]]; 
    }
    tot=0;
    get_sum(1,1,n,min(rnk[x],rnk[y]),max(rnk[x],rnk[y]));
    ans+=tot;
    return;
}

int main()
{
    //freopen("count1.in","r",stdin);
    //freopen("gun.out","w",stdout);
    scanf("%d",&n);
    for(register int i=1;i<=n-1;++i)
    {
        int s,e;
        scanf("%d%d",&s,&e);
        add_edge(s,e);
        add_edge(e,s);
    }
    for(register int i=1;i<=n;++i)
        scanf("%lld",&num[i]);
    memset(son,-1,sizeof(son));
    dfs_1(1,0);
    dfs_2(1,1);
    build(1,1,n);
    scanf("%d",&m);
    for(register int i=1;i<=m;++i)
    {
        char s[10];
        scanf("%s",s);
        int len=strlen(s);
        if(len==6)
        {
            int x;
            long long v;
            scanf("%d%lld",&x,&v);
            modify(1,1,n,rnk[x],rnk[x],v);
        }
        else if(len==4&&s[1]=='M')
        {
            int x,y;
            scanf("%d%d",&x,&y);
            ans=-1e18;
            tree_max(x,y);
            printf("%lld\n",ans);
        }
        else
        {
            int x,y;
            scanf("%d%d",&x,&y);
            ans=0;
            tree_sum(x,y);
            printf("%lld\n",ans); 
        }
    }    
    return 0;
}