SDOI2017 树点涂色

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define N 100050
inline int rd()
{
    int f=1,c=0;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){c=10*c+ch-‘0‘;ch=getchar();}
    return f*c;
}
int n,m,hed[N],cnt;
struct EG
{
    int to,nxt;
}e[2*N];
void ae(int f,int t)
{
    e[++cnt].to = t;
    e[cnt].nxt = hed[f];
    hed[f] = cnt;
}
int pla[N],dep[N];
struct segtree
{
    int mx[N<<2],tag[N<<2];
    void update(int u)
    {
        mx[u] = max(mx[u<<1],mx[u<<1|1]);
    }
    void add(int u,int d)
    {
        tag[u]+=d;
        mx[u]+=d;
    }
    void pushdown(int u)
    {
        if(tag[u])
        {
            add(u<<1,tag[u]);
            add(u<<1|1,tag[u]);
            tag[u] = 0;
        }
    }
    void build(int l,int r,int u)
    {
        if(l==r)
        {
            mx[u] = dep[pla[l]];
            return ;
        }
        int mid = (l+r)>>1;
        build(l,mid,u<<1);
        build(mid+1,r,u<<1|1);
        update(u);
    }
    void insert(int l,int r,int u,int ql,int qr,int d)
    {
        if(l==ql&&r==qr)
        {
            add(u,d);
            return ;
        }
        pushdown(u);
        int mid = (l+r)>>1;
        if(qr<=mid)insert(l,mid,u<<1,ql,qr,d);
        else if(ql>mid)insert(mid+1,r,u<<1|1,ql,qr,d);
        else insert(l,mid,u<<1,ql,mid,d),insert(mid+1,r,u<<1|1,mid+1,qr,d);
        update(u);
    }
    int query(int l,int r,int u,int ql,int qr)
    {
        if(l==ql&&r==qr)return mx[u];
        pushdown(u);
        int mid = (l+r)>>1;
        if(qr<=mid)return query(l,mid,u<<1,ql,qr);
        else if(ql>mid)return query(mid+1,r,u<<1|1,ql,qr);
        else return max(query(l,mid,u<<1,ql,mid),query(mid+1,r,u<<1|1,mid+1,qr));
    }
    int ask(int l,int r,int u,int qx)
    {
        if(l==r)return mx[u];
        pushdown(u);
        int mid = (l+r)>>1;
        if(qx<=mid)return ask(l,mid,u<<1,qx);
        else return ask(mid+1,r,u<<1|1,qx);
    }
}tr1;
int tin[N],tout[N],tim;
struct LCT
{
    int fa[N],ch[N][2];
    bool rt[N];
    void rotate(int x)
    {
        int y = fa[x],z = fa[y],k = (ch[y][1]==x);
        if(rt[y])rt[x]=1,rt[y]=0;
        else ch[z][ch[z][1]==y]=x;
        fa[x] = z;
        ch[y][k] = ch[x][!k],fa[ch[x][!k]] = y;
        ch[x][!k] = y,fa[y] = x;
    }
    void splay(int x)
    {
        while(!rt[x])
        {
            int y = fa[x],z = fa[y];
            if(!rt[y])
                (ch[y][1]==x)^(ch[z][1]==y)?rotate(x):rotate(y);
            rotate(x);
        }
    }
    int findroot(int x)
    {
        while(ch[x][0])x=ch[x][0];
        return x;
    }
    void access(int x)
    {
        int y = 0,v;
        while(x)
        {
            splay(x);
            if(ch[x][1])
            {
                v = findroot(ch[x][1]);
                tr1.insert(1,n,1,tin[v],tout[v],1);
            }
            if(y)
            {
                v = findroot(y);
                tr1.insert(1,n,1,tin[v],tout[v],-1);
            }
            rt[y]=0,rt[ch[x][1]]=1;
            ch[x][1] = y;
            y=x,x=fa[x];
        }
    }
}tr2;
int ff[N],son[N],siz[N],top[N];
void dfs1(int u,int f)
{
    siz[u]=1;
    ff[u]=f;
    tr2.fa[u]=f;
    tr2.rt[u]=1;
    dep[u]=dep[f]+1;
    for(int j=hed[u];j;j=e[j].nxt)
    {
        int to = e[j].to;
        if(to==f)continue;
        dfs1(to,u);
        siz[u]+=siz[to];
        if(siz[to]>siz[son[u]])son[u]=to;
    }
}
void dfs2(int u,int tp)
{
    top[u] = tp;
    tin[u] = ++tim;pla[tim] = u;
    if(son[u])
    {
        dfs2(son[u],tp);
        for(int j=hed[u];j;j=e[j].nxt)
        {
            int to = e[j].to;
            if(to==ff[u]||to==son[u])continue;
            dfs2(to,to);
        }
    }
    tout[u]=tim;
}
int get_lca(int x,int y)
{
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]])swap(x,y);
        x = ff[top[x]];
    }
    return dep[x]<dep[y]?x:y;
}
int main()
{
//    freopen("1.in","r",stdin);
    n = rd(),m = rd();
    for(int f,t,i=1;i<n;i++)
    {
        f=rd(),t=rd();
        ae(f,t),ae(t,f);
    }
    dfs1(1,0);
    dfs2(1,1);
    tr1.build(1,n,1);
    for(int opt,x,y,i=1;i<=m;i++)
    {
        opt = rd(),x = rd();
        if(opt==1)
        {
            tr2.access(x);
        }else if(opt==2)
        {
            y = rd();
            int k1 = tr1.ask(1,n,1,tin[x]);
            int k2 = tr1.ask(1,n,1,tin[y]);
            int lca = get_lca(x,y);
            int k3 = tr1.ask(1,n,1,tin[lca]);
            printf("%d\n",k1+k2-2*k3+1);
        }else
        {
            printf("%d\n",tr1.query(1,n,1,tin[x],tout[x]));
        }
    }
    return 0;
}