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| #define REP(i, s, e) for (int i = s; i <= e; i++)
#define DREP(i, s, e) for (int i = s; i >= e; i--)
#define view(u, i) for (int i(bg[u]); i; i = ne[i])
#define DEBUG fprintf(stderr, "Passing [%s] in Line %d\n", __FUNCTION__, __LINE__)
#define chkmax(a, b) a = max(a, b)
#define chkmin(a, b) a = min(a, b)
#include <iostream>
#include <cstdio>
using namespace std;
const int maxn = 1e5 + 10, maxm = maxn << 1;
int bg[maxn], ne[maxm], to[maxm], e;
inline void add(int x, int y)
{
e++;
to[e] = y;
ne[e] = bg[x];
bg[x] = e;
}
#define mid (l + r >> 1)
#define ls p << 1
#define rs p << 1 | 1
#define lson ls, l, mid
#define rson rs, mid + 1, r
#define get(u) (ch[fa[u]][1] == u)
#define notroot(u) (ch[fa[u]][0] == u || ch[fa[u]][1] == u)
int n, q;
int siz[maxn], dfn[maxn], back[maxn], dfs_clock, depth[maxn], top[maxn], hvy[maxn];
namespace tree
{
int fa[maxn];
void dfs1(int x)
{
siz[x] = 1;
view(x, i)
if (to[i] ^ fa[x])
{
depth[to[i]] = depth[fa[to[i]] = x] + 1;
dfs1(to[i]);
siz[x] += siz[to[i]];
if (siz[to[i]] > siz[hvy[x]]) hvy[x] = to[i];
}
}
void dfs2(int x, int y)
{
back[dfn[x] = ++dfs_clock] = x;
top[x] = y;
if (hvy[x]) dfs2(hvy[x], y);
view(x, i)
if (to[i] ^ fa[x] && to[i] ^ hvy[x]) dfs2(to[i], to[i]);
}
inline int lca(int x, int y)
{
while (top[x] ^ top[y])
{
if (depth[top[x]] < depth[top[y]]) swap(x, y);
x = fa[top[x]];
}
return depth[x] < depth[y] ? x : y;
}
}
using tree::lca;
int Max[maxn << 2], tag[maxn << 2];
inline void pushup(int p, int l, int r) {Max[p] = max(Max[ls], Max[rs]);}
void build(int p, int l, int r)
{
if (l == r) Max[p] = depth[back[l]] + 1;
else
{
build(lson);
build(rson);
pushup(p, l, r);
}
}
inline void work(int p, int val)
{
Max[p] += val;
tag[p] += val;
}
inline void pushdown(int p, int l, int r)
{
if (tag[p])
{
work(ls, tag[p]);
work(rs, tag[p]);
tag[p] = 0;
}
}
inline void add(int p, int l, int r, int L, int R, int val)
{
if (L <= l && r <= R) work(p, val);
else
{
pushdown(p, l, r);
if (L <= mid) add(lson, L, R, val);
if (R > mid) add(rson, L, R, val);
pushup(p, l, r);
}
}
inline int query(int p, int l, int r, int L, int R)
{
if (L <= l && r <= R) return Max[p];
else
{
pushdown(p, l, r);
if (L > mid) return query(rson, L, R);
if (R <= mid) return query(lson, L, R);
return max(query(lson, L, R), query(rson, L, R));
}
}
int ch[maxn][2], fa[maxn];
inline void rotate(int x)
{
int y(fa[x]);bool k(get(x));
ch[y][k] = ch[x][k ^ 1];
if (ch[x][k ^ 1]) fa[ch[x][k ^ 1]] = y;
ch[x][k ^ 1] = y;
if (notroot(y)) ch[fa[y]][get(y)] = x;
fa[x] = fa[y];
fa[y] = x;
}
void splay(int x)
{
int y = x, z(0);
while (notroot(x))
{
y = fa[x];z = fa[y];
if (notroot(y)) rotate((get(x) != get(y)) ? x : y);
rotate(x);
}
}
inline int rnxt(int u)
{
u = ch[u][1];
while (u && ch[u][0]) u = ch[u][0];
return u;
}
inline int sroot(int u)
{
while (u && ch[u][0]) u = ch[u][0];
return u;
}
inline void access(int x)
{
for (int u(0); x; u = x, x = fa[x])
{
splay(x);
int t1(rnxt(x)), t2(sroot(u));
ch[x][1] = u;
if (t1) add(1, 1, n, dfn[t1], dfn[t1] + siz[t1] - 1, 1);
if (t2) add(1, 1, n, dfn[t2], dfn[t2] + siz[t2] - 1, -1);
}
}
int main()
{
#ifdef CraZYali
freopen("2001.in", "r", stdin);
freopen("2001.out", "w", stdout);
freopen("2001.err", "w", stderr);
#endif
cin >> n >> q;
REP(i, 2, n)
{
int x, y;
scanf("%d%d", &x, &y);
add(x, y);add(y, x);
}
tree::dfs1(1);
tree::dfs2(1, 1);
REP(i, 1, n) fa[i] = tree::fa[i];
build(1, 1, n);
while (q--)
{
int opt, x;scanf("%d%d", &opt, &x);
if (opt == 1) access(x);
else if (opt == 2)
{
int y;scanf("%d", &y);
int l(lca(x, y)), ansx(query(1, 1, n, dfn[x], dfn[x])), ansy(query(1, 1, n, dfn[y], dfn[y])), ansl(query(1, 1, n, dfn[l], dfn[l]));
printf("%d\n", ansx + ansy - (ansl << 1) + 1);
}
else printf("%d\n", query(1, 1, n, dfn[x], dfn[x] + siz[x] - 1));
}
return 0;
}
|
