$19$ pts：

神秘 WA + RE

// 13:05
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define lc p<<1
#define rc p<<1|1
inline int in(){
	char a=getchar();int k=0,kk=1;
	while(!isdigit(a)){if(a=='-')kk=-1;a=getchar();}
	while(isdigit(a)){k=k*10+a-'0',a=getchar();}
	return k*kk;
}
const int N = 1e5 + 5;
struct node{int nxt,v;}e[2*N];
int head[N],tot,mod;
void add(int u,int v){e[++tot].v=v,e[tot].nxt=head[u],head[u] = tot;}
int son[N],siz[N],f[N],dep[N];
void dfs1(int x,int fa,int deep){
	f[x]=fa,siz[x]=1,dep[x]=deep;
	int maxson = -1;
	for(int i=head[x];i;i=e[i].nxt){
		int v = e[i].v;
		if(v!=fa){
			dfs1(v,x,deep+1);
			siz[x] += siz[v];
			if(siz[v]>maxson) maxson = siz[v],son[x] = v;
		}
	}
}
int id[N],wt[N],cnt,top[N],w[N]; 
void dfs2(int x,int topf){
	id[x] = ++cnt, wt[cnt] = w[x], top[x] = topf;
	if(!son[x]) return;
	dfs2(son[x],topf);
	for(int i=head[x];i;i=e[i].nxt){
		int v=e[i].v;
		if(v!=f[x]&&v!=son[x]){
			dfs2(v,v);
		}
	}
}
struct node1{int l,r,lazy,x;}tr[N*4];
void push_up(int p){tr[p].x=(tr[lc].x+tr[rc].x)%mod;}
void push_down(int p) {
	if(tr[p].lazy){
		int k = tr[p].lazy;
		tr[lc].x = (tr[lc].x + (tr[lc].r-tr[lc].l+1)*k%mod) % mod;
		tr[lc].lazy = (tr[lc].lazy + k) % mod;
		tr[rc].x = (tr[rc].x + (tr[rc].r-tr[rc].l+1)*k%mod) % mod;
		tr[rc].lazy = (tr[rc].lazy + k) % mod;
		tr[p].lazy = 0;
	}
}
void build(int p,int l,int r){
	tr[p].l = l, tr[p].r = r;
	if(l==r){
		tr[p].x = wt[l]%mod;
		return; 
	}
	int m = (l+r)>>1;
	build(lc,1,m),build(rc,m+1,r);
	push_up(p);
}
int query(int p,int l,int r){
	if(l<=tr[p].l&&r>=tr[p].r){
		return tr[p].x%mod;
	}
	push_down(p);
	int ans = 0,m = (tr[p].l+tr[p].r)/2;
	if(l<=m) ans = (ans +query(lc,l,r)) % mod;
	if(r>m) ans = (ans + query(rc,l,r)) % mod;
	return ans;
}
void change(int p,int l,int r,int k){
//	cout << p << " " << l << " " << r << " " << k << endl;
	k %= mod;
	if(l<=tr[p].l&&r>=tr[p].r){
		tr[p].x = (tr[p].x + (tr[p].r-tr[p].l+1)*k%mod) % mod;
		tr[p].lazy = (tr[p].lazy + k) % mod;
		return;
	}
	push_down(p);
	int m = (tr[p].l+tr[p].r)/2;
	if(l<=m) change(lc,l,r,k);
	if(r>m) change(rc,l,r,k);
	push_up(p);
}
int tr_query(int x,int y){
	int ans = 0;
	while(top[x]!=top[y]){
		if(dep[top[x]]<dep[top[y]]) swap(x,y);
		ans = (ans + query(1,id[top[x]],id[x]) % mod) % mod;
		x = f[top[x]];
	}
	if(dep[x]>dep[y]) swap(x,y);
	ans = (ans + query(1,id[x],id[y])) % mod;
	return ans;
}
void tr_change(int x,int y,int k){
	k %= mod;
	while(top[x]!=top[y]){
		if(dep[top[x]]<dep[top[y]]) swap(x,y);
		change(1,id[top[x]],id[x],k);
		x = f[top[x]];
	}
	if(dep[x]>dep[y]) swap(x,y);
	change(1,id[x],id[y],k);
}
void tmpadd(int x,int k){
	k %= mod;
	change(1,id[x],id[x]+siz[x]-1,k);
}
int tmpquery(int x){
	return query(1,id[x],id[x]+siz[x]-1) % mod;
}
int n,m,r;
signed main(){
//	freopen("P3384_1.in","r",stdin);
//	freopen("mine.txt","w",stdout);
	n = in(), m = in(), r = in(), mod = in();
	for(int i=1;i<=n;i++) w[i] = in();
	for(int i=1;i<n;i++){
		int u = in(), v = in();
		add(u,v), add(v,u);
	}
	dfs1(r,0,1);
	dfs2(r,r);
	build(1,1,n);
//	for(int i=1;i<=n;i++) cout << top[i] << " ";
//	puts("");
	while(m--){ 
		int op = in(), x = in(),y,z;
		if(op==1){
			y=in(),z=in();
			tr_change(x,y,z);
		}else if(op==2){
			y = in();
			printf("%lld\n",tr_query(x,y)%mod);
		}else if(op==3){
			y = in();
			tmpadd(x,y);
		}else{
			printf("%lld\n",tmpquery(x)%mod);
		}
	}
	return 0;
}

AC

// 20:26:30
#include<bits/stdc++.h>
using namespace std;

#define lc p<<1
#define rc p<<1|1
#define int long long
const int N = 1e5 + 5;

struct node{
	int v,nxt;
}e[N*2];
struct node1{
	int x,l,r,lazy;
}tr[N<<2];
int n,m,r,head[N],mod,tot,w[N],wt[N];
void add(int u,int v){
	e[++tot].v = v;
	e[tot].nxt = head[u];
	head[u] = tot;
}
void push_up(int p){
	tr[p].x = (tr[lc].x + tr[rc].x) % mod;
}
void push_down(int p){
	if(tr[p].lazy){
		int k = tr[p].lazy;
		tr[lc].x = (tr[lc].x+(tr[lc].r-tr[lc].l+1)*k) % mod;
		tr[rc].x = (tr[rc].x+(tr[rc].r-tr[rc].l+1)*k) % mod;
		tr[lc].lazy = (tr[lc].lazy+k) % mod;
		tr[rc].lazy = (tr[rc].lazy+k) % mod;
		tr[p].lazy = 0;
	}
}
void build(int p,int l,int r){
	tr[p].l = l, tr[p].r = r;
	if(l==r){
		tr[p].x = wt[l] % mod;
		return;
	}
	int m = l + r >> 1;
	build(lc,l,m),build(rc,m+1,r),push_up(p);
} 
int query(int p,int l,int r){
	if(l<=tr[p].l&&r>=tr[p].r){
		return tr[p].x % mod;
	}
	push_down(p);
	int ans = 0, m = tr[p].l + tr[p].r >> 1;
	if(l<=m) ans += query(lc,l,r) % mod;
	if(r>m) ans = (ans + query(rc,l,r)) % mod;
	return ans;
}
void change(int p,int l,int r,int k){
	if(l<=tr[p].l&&r>=tr[p].r){
		tr[p].x = (tr[p].x+(tr[p].r-tr[p].l+1)*k) % mod;
		tr[p].lazy = (tr[p].lazy+k) % mod;
		return;
	}
	push_down(p);
	int m = tr[p].l + tr[p].r >> 1;
	if(l<=m) change(lc,l,r,k);
	if(r>m) change(rc,l,r,k);
	push_up(p);
}

inline int in(){
	char a=getchar();
	int k=0,kk=1;
	while(a>'9'||a<'0'){
		if(a=='-') kk = -1;
		a = getchar();
	}
	while(a>='0'&&a<='9'){
		k=k*10+a-'0',a=getchar();
	}
	return k*kk;
}
int dep[N],fa[N],son[N],siz[N],id[N],top[N],cnt;
void dfs1(int x,int f,int deep){
	fa[x] = f, dep[x] = deep, siz[x] = 1;
	int maxson = -1;
	for(int i=head[x];i;i=e[i].nxt){
		int v = e[i].v;
		if(v==f) continue;
		dfs1(v,x,deep+1);
		siz[x] += siz[v];
		if(siz[v]>maxson) son[x] = v, maxson = siz[v];
	}
}
void dfs2(int x,int topf){
	top[x] = topf, id[x] = ++cnt, wt[cnt] = w[x];
	if(!son[x]) return;
	dfs2(son[x],topf);
	for(int i=head[x];i;i=e[i].nxt){
		int v = e[i].v;
		if(v==fa[x]||v==son[x]) continue;
		dfs2(v,v);
	}
}

void tr_change(int x,int y,int k){
	while(top[x]!=top[y]){
		if(dep[top[x]]<dep[top[y]]) swap(x,y);
		change(1,id[top[x]],id[x],k);
		x = fa[top[x]];
	}
	if(dep[x]>dep[y]) swap(x,y);
	change(1,id[x],id[y],k);
}
int tr_query(int x,int y){
	int ans = 0;
	while(top[x]!=top[y]){
		if(dep[top[x]]<dep[top[y]]) swap(x,y);
		ans = (ans + query(1,id[top[x]],id[x])) % mod;
		x = fa[top[x]];
	}
	if(dep[x]>dep[y]) swap(x,y);
	ans = (ans + query(1,id[x],id[y])) % mod;
	return ans;	
}
void tr_upson(int x,int k){
	change(1,id[x],id[x]+siz[x]-1,k);
}
int tr_qson(int x){
	return query(1,id[x],id[x]+siz[x]-1) % mod;
}
signed main(){
	n = in(), m = in(), r = in(), mod = in();
	for(int i=1;i<=n;i++) w[i] = in();
	for(int i=1;i<n;i++){
		int u=in(),v=in();
		add(u,v),add(v,u);
	}
	dfs1(r,0,1);
	dfs2(r,r);
	build(1,1,n);
	while(m--){
		int op = in(), x = in(), y,z;
		if(op==1){
			y = in(), z = in();
			tr_change(x,y,z);
		}else if(op==2){
			y = in();
			printf("%lld\n",tr_query(x,y));
		}else if(op==3){
			y = in();
			tr_upson(x,y);
		}else{
			printf("%lld\n",tr_qson(x));
		}
	}
	return 0;
}

PS:和好基友比赛默写薯片结果调到现在，破防。