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| #include <bits/stdc++.h>
#define MAXN 200005
#define MAXM 25
using namespace std;
inline int read(){
int x=0,f=1;
char ch=getchar();
while (ch<'0'||ch>'9'){
if (ch=='-') f=-1;
ch=getchar();
}
while (ch>='0'&&ch<='9'){
x=(x<<3)+(x<<1)+(ch^'0');
ch=getchar();
}
return x*f;
}
vector<int>G[MAXN];
inline void AddEdge(int u,int v){
G[u].push_back(v);
}
int a[MAXN];
int fa[MAXN],dep[MAXN],top[MAXN],sz[MAXN],tofa[MAXN],son[MAXN];
int anc[MAXN][MAXM];
void dfs1(int u,int father){
sz[u]=1;
anc[u][0]=father;
for (register int i=1;i<MAXM;++i){
anc[u][i]=anc[anc[u][i-1]][i-1];
}
for (register int i=0;i<G[u].size();++i){
int v=G[u][i];
if (v!=father){
dep[v]=dep[u]+1;
fa[v]=u;
dfs1(v,u);
sz[u]+=sz[v];
if (sz[son[u]]<sz[v]) son[u]=v;
}
}
}
int L[MAXN],R[MAXN],seq[MAXN],cnt;
void dfs2(int u,int t){
if (!u) return ;
seq[L[u]=++cnt]=u;
top[u]=t;
dfs2(son[u],t);
for (register int i=0;i<G[u].size();++i){
int v=G[u][i];
if (v!=son[u]&&v!=fa[u]){
dfs2(v,v);
}
}
R[u]=cnt;
}
inline int LCA(int u,int v){
if (u==1||v==1) return 1;
if (dep[u]<dep[v]) swap(u,v);
for (register int i=MAXM-1;i>=0;--i){
if (dep[anc[u][i]]>=dep[v]){
u=anc[u][i];
}
}
if (u==v) return u;
for (register int i=MAXM-1;i>=0;--i){
if (anc[u][i]!=anc[v][i]){
u=anc[u][i],v=anc[v][i];
}
}
return anc[u][0];
}
inline int Hop(int u,int lca){
for (register int i=MAXM-1;i>=0;--i){
if (dep[anc[u][i]]>dep[lca]) {
u=anc[u][i];
}
}
return u;
}
int val[MAXN];
namespace SegmentTree{
struct node{
int l,r;
int mino,tag;
}tree[MAXN<<1];
#define lc i<<1
#define rc i<<1|1
inline void Cover(int i,int val){
tree[i].mino=tree[i].tag=val;
}
inline void pushup(int i){
tree[i].mino=min(tree[lc].mino,tree[rc].mino);
}
inline void pushdown(int i){
if (tree[i].tag!=-1){
Cover(lc,tree[i].tag);
Cover(rc,tree[i].tag);
tree[i].tag=-1;
}
}
void Build(int i,int l,int r){
tree[i].l=l,tree[i].r=r;
tree[i].tag=-1;
if (l==r){
tree[i].mino=a[seq[l]];
return ;
}
int mid=(l+r)>>1;
Build(lc,l,mid);
Build(rc,mid+1,r);
pushup(i);
}
void Update(int i,int L,int R,int val){
if (L<=tree[i].l&&tree[i].r<=R){
Cover(i,val);
return ;
}
int mid=(tree[i].l+tree[i].r)>>1;
pushdown(i);
if (L<=mid) Update(lc,L,R,val);
if (mid<R) Update(rc,L,R,val);
pushup(i);
}
int Query(int i,int L,int R){
if (L<=tree[i].l&&tree[i].r<=R){
return tree[i].mino;
}
int mid=(tree[i].l+tree[i].r)>>1,ans=0x7fffffff;
pushdown(i);
if (L<=mid) ans=min(ans,Query(lc,L,R));
if (mid<R) ans=min(ans,Query(rc,L,R));
return ans;
}
}
using namespace SegmentTree;
inline void UpdateChain(int u,int v,int val){
while (top[u]!=top[v]){
if (dep[top[u]]<dep[top[v]]) swap(u,v);
Update(1,L[top[u]],L[u],val);
u=anc[top[u]][0];
}
if (dep[u]>dep[v]) swap(u,v);
Update(1,L[u],L[v],val);
}
int main(){
int n=read(),m=read();
for (register int i=1;i<n;++i){
int u=read(),v=read();
AddEdge(u,v);
AddEdge(v,u);
}
for (register int i=1;i<=n;++i){
a[i]=read();
}
dfs1(1,0);
dfs2(1,1);
Build(1,1,n);
int rt=read();
while (m--){
int opr=read();
if (opr==1){
rt=read();
}
else if (opr==2){
int u=read(),v=read(),val=read();
UpdateChain(u,v,val);
}
else if (opr==3){
int u=read();
if (u==rt){
printf("%d\n",Query(1,1,n));
}
else if (LCA(u,rt)==u){
int v=Hop(rt,u);
printf("%d\n",min(Query(1,1,L[v]-1),Query(1,R[v]+1,n)));
}
else {
printf("%d\n",Query(1,L[u],R[u]));
}
}
}
}
|
