调两天了，就过了两个点。。。

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=1e6+5;
int lazy[4*N],wt[N],n,m,p,root,first[N],cnt,a[4*N],size[N],top[N],son[N],dep[N],fa[N],id[N],tot;
struct data{
	int nex,to;
}f[2*N];
void l(int x,int y)
{
	f[++cnt].nex=first[x];
	first[x]=cnt;
	f[cnt].to=y;
}
void init()
{
	cin>>n>>m>>root>>p;
	for(int i=1;i<=n;i++)
	{
		scanf("%lld",&a[i]);
	}
	for(int i=1;i<=n-1;i++)
	{
		int x,y;
		scanf("%lld%lld",&x,&y);
		l(x,y);
		l(y,x);
	}
}
void dfs1(int x,int fath,int d)
{
	dep[x]=d;
	fa[x]=fath;
	size[x]=1;
	for(int i=first[x];i;i=f[i].nex)
	{
		int to=f[i].to;
		if(to==fath)continue;
		dfs1(to,x,d+1);
		size[x]+=size[to];
		if(size[to]>size[son[x]])son[x]=to;
	}
	
}
void dfs2(int x,int topf)
{
	id[x]=++tot;
	wt[tot]=a[x];
	top[x]=topf;
	if(!son[x])return;
	dfs2(son[x],topf);
	for(int i=first[x];i;i=f[i].nex)
	{
		int to=f[i].to;
		if(to==fa[x]||to==son[x])continue;
		dfs2(to,to);
	}
}
void build(int k,int l,int r)
{
	if(l==r)
	{
		a[k]=wt[l];
		a[k]%=p;return;
	}
	int mid=(l+r)/2;
	build(k*2,l,mid);
	build(k*2+1,mid+1,r);
	a[k]=(a[k*2]+a[k*2+1])%p;
}
void pushdown(int k,int l,int r)
{
	lazy[k*2]+=lazy[k];
	lazy[k*2+1]+=lazy[k];
	a[k*2]+=lazy[k]*((r-l+1)-(r-l+1)/2);
	a[k*2+1]+=lazy[k]*((r-l+1)/2);
	a[k*2]%=p;
	a[k*2+1]%p;
	lazy[k*2]%=p;
	lazy[k*2+1]%=p;
	lazy[k]=0;
}
void updata(int k,int l,int r,int x,int y,int z)
{
	if(x<=l&&r<=y)
	{
		lazy[k]+=z;
		a[k]+=z*(r-l+1);
		return;
	}
	else
	{
		int mid=(l+r)/2;
		if(lazy[k])pushdown(k,l,r);
		if(x<=mid)
		updata(k*2,l,mid,x,y,z);
		if(y>mid)
		updata(k*2+1,mid+1,r,x,y,z);
		a[k]=(a[k*2]+a[k*2+1])%p;
	}	
}
void modify(int x,int y,int z)
{
	
	z%=p;
	while(top[x]!=top[y])
	{
		if(dep[top[x]]<dep[top[y]])swap(x,y);
		updata(1,1,n,id[top[x]],id[x],z);
		x=fa[top[x]];
	}
	if(dep[x]>dep[y])
	swap(x,y);
	updata(1,1,n,id[x],id[y],z);
}
void modifys(int x,int z)
{
	updata(1,1,n,id[x],id[x]+size[x]-1,z%p);
}
int que(int k,int l,int r,int x,int y)
{
	int ans=0;
	if(x<=l&&r<=y)
	{
		return a[k]%p;
	}
	else
	{
		if(lazy[k])pushdown(k,l,r);
		int mid=(l+r)/2;
		if(x<=mid)ans+=que(k*2,l,mid,x,y);
		if(y>mid)ans+=que(k*2+1,mid+1,r,x,y);
		ans%=p;
		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+=que(1,1,n,id[top[x]],id[x]);
		x=fa[top[x]];
		ans%=p;
	}
	if(dep[x]>dep[y])swap(dep[x],dep[y]);
	ans+=que(1,1,n,id[x],id[y]);
	ans%=p;
	return ans;
} 
int querys(int x)
{
	return que(1,1,n,id[x],id[x]+size[x]-1);
}
void solve()
{
	dfs1(root,0,1);
	dfs2(root,root);
	memset(a,0,sizeof(a));
	build(1,1,n);
	while(m--)
	{
		int x,y,z,k;
		scanf("%lld",&k);
		if(k==1)
		{
			scanf("%lld%lld%lld",&x,&y,&z);
			modify(x,y,z);
		}
		else if(k==2)
		{
			scanf("%lld%lld",&x,&y);
			printf("%lld\n",query(x,y));
		}
		else if(k==3)
		{
			scanf("%lld%lld",&x,&y);
			modifys(x,y);
		}
		else if(k==4)
		{
			scanf("%lld",&x);
			printf("%lld\n",querys(x));
		}
	}
}
signed main()
{
	init();
	solve();
	return 0;
}