一半WA还有一半RE求调

代码：

#include<bits/stdc++.h>
using namespace std;
const int N=2e5+10; 
int n,m,root,P;
int a[N];int top[N];
int son[N];
int dep[N];
int fa[N];
int dfn[N];
int rnk[N];
int siz[N];
int bot[N];
vector<int> g[N]; 
void dfs1(int u)
{
	son[u]=-1;
	siz[u]=1;
	for(int i=0;i<g[u].size();i++)
	{
		int v=g[u][i];
		if(!dep[v])
		{
			dep[v]=dep[u]+1;
			fa[v]=u;
			dfs1(v);
			siz[u]+=siz[v];
			if(son[u]==-1||siz[v]>siz[v])son[u]=v;
		}
	}
}
int cnt;
void dfs2(int u,int t)
{
	top[u]=t;
	dfn[u]=++cnt;
	bot[u]=cnt;
	rnk[cnt]=u;
	if(son[u]!=-1)	dfs2(son[u],t);
	cout<<u<<endl;
	for(int i=0;i<g[u].size();i++)
	{
		int v=g[u][i];
		if(v!=fa[u]&&v!=son[u]){
			dfs2(v,v);
			bot[u]=max(bot[v],bot[u]);
		}
	}
}
#define lson (rt<<1)
#define rson (rt<<1|1)
#define mid ((l+r)>>1)
struct Tree
{
    int l,r,lazy,v;
}tr[N<<2];
void pushup(int rt)
{
    tr[rt].v=tr[lson].v+tr[rson].v;
    tr[rt].v%=P;
}
void pushdown(int rt)
{
    int ll=tr[lson].l,lr=tr[lson].r;
    int rl=tr[rson].l,rr=tr[rson].r; 
    tr[lson].v+=(lr-ll+1)*tr[rt].lazy;
    tr[lson].v%=P;
    tr[lson].lazy+=tr[rt].lazy;
    tr[lson].lazy%=P;
    tr[rson].v+=(rr-rl+1)*tr[rt].lazy;
    tr[rson].v=P;
    tr[rson].lazy+=tr[rt].lazy;
    tr[rson].lazy%=P;
    tr[rt].lazy=0;
}
void build(int rt,int l,int r)
{
    tr[rt]={l,r,0,0};
    if(l==r)
    {
        tr[rt].v=a[l];
        tr[rt].v%=P;
        return;
    }
    build(lson,l,mid);
    build(rson,mid+1,r);
    pushup(rt); 
}
void update(int rt,int sp,int ep,int k)
{
    int l=tr[rt].l,r=tr[rt].r;
    if(sp<=l&&r<=ep)
    {
        tr[rt].v+=(r-l+1)*k;
        tr[rt].v%=P;
        tr[rt].lazy+=k;
        tr[rt].lazy%=P;
        return ;
    }
    pushdown(rt);
    if(sp<=mid)
    {
        update(lson,sp,ep,k);
    }
    if(ep>mid)
    {
        update(rson,sp,ep,k);
    }
    pushup(rt);
}
int query(int rt,int sp,int ep)
{
    int l=tr[rt].l,r=tr[rt].r;
    if(sp<=l&&r<=ep)
    {
        return tr[rt].v;
    }
    pushdown(rt);
    if(ep<=mid)
    {
        return query(lson,sp,ep);
    }
    if(sp>mid)
    {
        return query(rson,sp,ep);
    }
    int L=query(lson,sp,ep);
    int R=query(rson,sp,ep);
    return (L+R)%P;
}
#undef lson
#undef rson
#undef mid 
void add_path(int x,int y,int k)
{
	while(top[x]!=top[y])
	{
		if(dep[top[x]]<dep[top[y]])swap(x,y);
		update(1,dfn[x],dfn[top[x]],k);
		x=fa[x];	
	}
	if(dep[x]<dep[y])swap(x,y);
	update(1,dfn[y],dfn[x],k);
}

int sum_path(int x,int y)
{
	int res=0;
	while(top[x]!=top[y])
	{
		if(dep[top[x]]<dep[top[y]])swap(x,y);
		res+=query(1,dfn[x],dfn[top[x]]);
		res%=P;
		x=fa[x];	
	}
	if(dep[x]<dep[y])swap(x,y);
	res+=query(1,dfn[y],dfn[x]);
	return res%P;
}
void add_subtree(int x,int k)
{
//	cout<<dfn[x]<<" "<<bot[x]<<endl;	
	update(1,dfn[x],bot[x],k);
}
int sum_subtree(int x)
{
	return query(1,dfn[x],bot[x])%P;
}
int main()
{
	cin>>n>>m>>root>>P;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
	}
	for(int i=1;i<n;i++)
	{
		int x,y;
		cin>>x>>y;
		g[x].push_back(y);
		g[y].push_back(x); 
	 } 
	 dep[root]=1;
	 fa[root]=0;
	 dfs1(root);
	 cout<<1;
	 dfs2(root,root); 
	build(1,1,n);
	while(m--)
	{
		int op;
		cin>>op;
		if(op==1)
		{
			int x,y,z;
			cin>>x>>y>>z;
			add_path(x,y,z);
		}
		if(op==2)
		{
			int x,y;
			cin>>x>>y;
			cout<<sum_path(x,y)<<endl;
		}
		if(op==3)
		{
			int x,y;
			cin>>x>>y;
			add_subtree(x,y);
		}
		if(op==4)
		{
			int x;
			cin>>x;
			cout<<sum_subtree(x)<<endl;
		}
	 } 
	return 0;
 }