rt,#5链的时候寄了

#include <bits/stdc++.h>
#define rg register
#define il inline
#define rep(i,a,b) for(rg int i=(a);i<=(b);++i)
#define sqr(x) ((x)*(x))
using namespace std;
const int INF=0x3f3f3f3f;
inline int read()
{
    int w=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
    {
        if(ch=='-') f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9')
    {
        w=(w<<1)+(w<<3)+(ch^48);
        ch=getchar();
    }
    return w*f;
}
inline void write(int x)
{
    if(x<0)
    {
        putchar('-');
        x=-x;
    }
    if(x>9) write(x/10);
    putchar(x%10+'0');
}

const int N=100010;
int n,m,a[N],rt;
vector<int> G[N];
int dep[N],sz[N],hson[N],fa[N];
void dfs1(int u,int f)
{
    dep[u]=dep[f]+1,sz[u]=1,fa[u]=f;
    int hson_sz=-1;
    for(int v:G[u])
    {
        if(v==f) continue;
        dfs1(v,u);
        sz[u]+=sz[v];
        if(hson_sz<sz[v])
        {
            hson_sz=sz[v];
            hson[u]=v;
        }
    }
}
int top[N],dfn[N],rnk[N],cnt;
void dfs2(int u,int f)
{
    top[u]=f,dfn[u]=++cnt,rnk[cnt]=u;
    if(!hson[u]) return;
    dfs2(hson[u],f);
    for(int v:G[u])
    {
        if(v==hson[u]||v==fa[u]) continue;
        dfs2(v,v);
    }
}
il int get_son(int u,int v)
{
    while(top[u]!=top[v])
    {
        if(dep[top[u]]<dep[top[v]]) swap(u,v);
        if(fa[top[u]]==v) return top[u];
        u=fa[top[u]];
    }
    if(dep[u]<dep[v]) return hson[v];
    else return hson[u];
}
#define ls(p) p<<1
#define rs(p) p<<1|1
const int flag=-1;
struct node
{
    int l,r,minn,tag;
    node()
    {
		l=r=0;
		tag=flag;
		minn=2e9;
	}
}tr[N<<2];
void pushup(int p)
{
    tr[p].minn=min(tr[ls(p)].minn,tr[rs(p)].minn);
}
void pushdown(int p)
{
    if(tr[p].tag!=flag)
    {
        tr[ls(p)].tag=tr[ls(p)].minn=tr[p].tag;
        tr[rs(p)].tag=tr[rs(p)].minn=tr[p].tag;
        tr[p].tag=flag;
    }
}
void build(int p,int L,int R)
{
    tr[p].l=L,tr[p].r=R,tr[p].tag=flag;
    if(L==R)
    {
        tr[p].minn=a[rnk[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 k)
{
//    if(tr[p].l>R||L>tr[p].r) return;
    if(L<=tr[p].l&&tr[p].r<=R)
    {
        tr[p].minn=tr[p].tag=k;
        return;
    }
    pushdown(p);
    int mid=(tr[p].l+tr[p].r)>>1;
    if(mid>=L) update(ls(p),L,R,k);
    if(mid<R) update(rs(p),L,R,k);
    pushup(p);
}
int query(int p,int L,int R)
{
    if(tr[p].l>R||tr[p].r<L) return 2e9;
    if(L<=tr[p].l&&tr[p].r<=R)
    {
        return tr[p].minn;
    }
    pushdown(p);
    int mid=(tr[p].l+tr[p].r)>>1,minn=2e9;
    if(mid>=L) minn=min(minn,query(ls(p),L,R));
    if(mid<R) minn=min(minn,query(rs(p),L,R));
    return minn;
}
il void update_path(int u,int v,int k)
{
    while(top[u]!=top[v])
    {
        if(dep[top[u]]<dep[top[v]])
        {
            swap(u,v);
        }
        update(1,dfn[top[u]],dfn[u],k);
        u=fa[top[u]];
    }
    if(dep[u]<dep[v]) swap(u,v);
    update(1,dfn[v],dfn[u],k);
}
il int query_tree(int u)
{
//    cout<<u<<endl;
    if(u==rt)
    {
        return query(1,1,n);
    }
    else if(dfn[rt]>=dfn[u]&&dfn[rt]<=dfn[u]+sz[u]-1)
    {
        int s=get_son(u,rt);
        return min(query(1,1,dfn[s]-1),query(1,dfn[s]+sz[s],n));
    }
    else return query(1,dfn[u],dfn[u]+sz[u]-1);
}

int main()
{
    #ifndef ONLINE_JUDGE
//    freopen("in.txt","r",stdin);
//    freopen("out.txt","w",stdout);
    #endif
    n=read(),m=read();
    for(int i=1,u,v;i<n;++i)
    {
        u=read(),v=read();
        G[u].push_back(v),G[v].push_back(u);
    }
    for(int i=1;i<=n;++i) a[i]=read();
    rt=read();
    dfs1(1,0),dfs2(1,1);
    build(1,1,n);
    for(int i=1,opt,x,y,v;i<=m;++i)
    {
        opt=read();
        if(opt==1)
        {
            rt=read();
        }
        else if(opt==2)
        {
            x=read(),y=read(),v=read();
            update_path(x,y,v);
        }
        else
        {
            x=read();
            printf("%d\n",query_tree(x));
        }
    }
    return 0;
}