各位大佬能帮忙调调P2590吗？心态崩了

#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,m,rt=1,l,r,v,x,y,tot,sz[100001],son[100001],rev[100001],a[100001],fa[100001],dep[100001],id[100001],top[100001];
char k[200];
vector<int>g[100001];
struct {
    int sum,max;
}sg[120001];
inline int ls(int p){return p<<1;}
inline int rs(int p){return p<<1|1;}
void dfs1(int u,int f,int d){
    dep[u]=d;
    fa[u]=f;
    sz[u]=1;
    int ms=0;
    for(int i=0;i<g[u].size();i++){
        int v=g[u][i];
        if(v==f)continue;
        dfs1(v,u,d+1);
        sz[u]+=sz[v];
        if(sz[v]>ms)ms=sz[v],son[u]=v;
    }
}
void dfs2(int u,int t){
    id[u]=++tot;
    rev[tot]=a[u];
    top[u]=t;
    if(!son[u])return ;
    dfs2(son[u],t);
    for(int i=0;i<g[u].size();i++){
        int v=g[u][i];
        if(id[v])continue;
        dfs2(v,v);
    }
}
inline void pushup(int p){sg[p].sum=sg[ls(p)].sum+sg[rs(p)].sum;sg[p].max=max(sg[ls(p)].max,sg[rs(p)].max);}
void build(int p,int l,int r){
    if(l==r){
        sg[p].sum=sg[p].max=rev[l];
        return ;
    }
    int mid=l+r>>1;
    build(ls(p),l,mid);
    build(rs(p),mid+1,r);
    pushup(p);
}
void update(int p,int l,int r,int x,int v){
    if(l==r){
        sg[p].max=sg[p].sum=v;
        return ;
    }
    int mid=l+r>>1;
    if(x<=mid)update(ls(p),l,mid,x,v);
    else update(rs(p),mid+1,r,x,v);
    pushup(p);
}
int sum(int p,int l,int r,int x,int y){
    if(x<=l&&r<=y)return sg[p].sum;
    int mid=l+r>>1,ans=0;
    if(x<=mid)ans+=sum(ls(p),l,mid,x,y);
    if(y>mid)ans+=sum(rs(p),mid+1,r,x,y);
    return ans;
}
int maxn(int p,int l,int r,int x,int y){
    if(x<=l&&r<=y)return sg[p].max;
    int mid=l+r>>1,ans=-0x3f3f3f3f;
    if(x<=mid)ans=max(ans,maxn(ls(p),l,mid,x,y));
    if(y>mid)ans=max(ans,maxn(rs(p),mid+1,r,x,y));
    return ans;
}
int ask(int x,int y){
    int ans=-0x3f3f3f3f;
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]])swap(x,y);
        ans=max(ans,maxn(1,1,n,id[top[x]],id[x]));
        x=fa[top[x]];
    }
    if(dep[x]>dep[y])swap(x,y);
    ans=max(ans,maxn(1,1,n,id[x],id[y]));
    return ans;
}
int query(int x,int y){
    int ans=0;
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]])swap(x,y);
        ans+=sum(1,1,n,id[top[x]],id[x]);
        x=fa[top[x]];
    }
    if(dep[x]>dep[y])swap(x,y);
    ans+=sum(1,1,n,id[x],id[y]);
    return ans;
}
signed main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++)cin>>a[i];
    for(int i=1;i<n;i++){
        cin>>x>>y;
        g[x].push_back(y);
    }
    dfs1(rt,-1,1);
    dfs2(rt,rt);
    build(1,1,n);
    while(m--){
        cin>>k>>l>>r;
        switch(k[1]){
            case 'H':update(1,1,n,id[l],r);break;
            case 'S':cout<<query(l,r);putchar('\n');break;
            case 'M':cout<<ask(l,r);putchar('\n');break;
        }
    }
}

@TMJYH09 大佬来看看啦