[HNOI2016]网络 [树链剖分，可删除堆]

考虑在 |不在| 这条链上的所有点上放上一个 \(x\)，删除也是，然后用可删除堆就随便草掉了。

// powered by c++11
// by Isaunoya
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
#define rep(i, x, y) for (register int i = (x); i <= (y); ++i)
#define Rep(i, x, y) for (register int i = (x); i >= (y); --i)
using namespace std;
using db = double;
using ll = long long;
using uint = unsigned int;
using pii = pair<int, int>;
#define ve vector
#define Tp template
#define all(v) v.begin(), v.end()
#define sz(v) ((int)v.size())
#define pb emplace_back
#define fir first
#define sec second
// the cmin && cmax
Tp<class T> void cmax(T& x, const T& y) {
  if (x < y) x = y;
}
Tp<class T> void cmin(T& x, const T& y) {
  if (x > y) x = y;
}
// sort , unique , reverse
Tp<class T> void sort(ve<T>& v) { sort(all(v)); }
Tp<class T> void unique(ve<T>& v) {
  sort(all(v));
  v.erase(unique(all(v)), v.end());
}
Tp<class T> void reverse(ve<T>& v) { reverse(all(v)); }
const int SZ = 0x191981;
struct FILEIN {
  char qwq[SZ], *S = qwq, *T = qwq, ch;
  char GETC() { return (S == T) && (T = (S = qwq) + fread(qwq, 1, SZ, stdin), S == T) ? EOF : *S++; }
  FILEIN& operator>>(char& c) {
    while (isspace(c = GETC()))
      ;
    return *this;
  }
  FILEIN& operator>>(string& s) {
    while (isspace(ch = GETC()))
      ;
    s = ch;
    while (!isspace(ch = GETC())) s += ch;
    return *this;
  }
  Tp<class T> void read(T& x) {
    bool sign = 1;
    while ((ch = GETC()) < 0x30)
      if (ch == 0x2d) sign = 0;
    x = (ch ^ 0x30);
    while ((ch = GETC()) > 0x2f) x = x * 0xa + (ch ^ 0x30);
    x = sign ? x : -x;
  }
  FILEIN& operator>>(int& x) { return read(x), *this; }
  FILEIN& operator>>(unsigned& x) { return read(x), *this; }
} in;
struct FILEOUT {
  const static int LIMIT = 0x114514;
  char quq[SZ], ST[0x114];
  signed sz, O;
  ~FILEOUT() { flush(); }
  void flush() {
    fwrite(quq, 1, O, stdout);
    fflush(stdout);
    O = 0;
  }
  FILEOUT& operator<<(char c) { return quq[O++] = c, *this; }
  FILEOUT& operator<<(string str) {
    if (O > LIMIT) flush();
    for (char c : str) quq[O++] = c;
    return *this;
  }
  Tp<class T> void write(T x) {
    if (O > LIMIT) flush();
    if (x < 0) {
      quq[O++] = 0x2d;
      x = -x;
    }
    do {
      ST[++sz] = x % 0xa ^ 0x30;
      x /= 0xa;
    } while (x);
    while (sz) quq[O++] = ST[sz--];
    return;
  }
  FILEOUT& operator<<(int x) { return write(x), *this; }
  FILEOUT& operator<<(unsigned x) { return write(x), *this; }
} out;

int n, m;
struct P {
  priority_queue<int> a, b;
  inline void push(int x) { a.push(x); }
  inline void erase(int x) { b.push(x); }
  inline int top() {
    while (!a.empty() && !b.empty() && a.top() == b.top()) a.pop(), b.pop();
    if (a.empty()) return -1;
    return a.top();
  }
};
const int maxn = 1e5 + 51;
P s[maxn << 2];
void upd(int a, int b, int l, int r, int rt, int x) {
  if (a <= l && r <= b) {
    s[rt].push(x);
    return;
  }
  int mid = l + r >> 1;
  if (a <= mid) upd(a, b, l, mid, rt << 1, x);
  if (b > mid) upd(a, b, mid + 1, r, rt << 1 | 1, x);
}
void erase(int a, int b, int l, int r, int rt, int x) {
  if (a <= l && r <= b) {
    s[rt].erase(x);
    return;
  }
  int mid = l + r >> 1;
  if (a <= mid) erase(a, b, l, mid, rt << 1, x);
  if (b > mid) erase(a, b, mid + 1, r, rt << 1 | 1, x);
}
int ans = -1;
void qry(int l, int r, int x, int rt) {
  cmax(ans, s[rt].top());
  if (l == r) return;
  int mid = l + r >> 1;
  (x <= mid) ? qry(l, mid, x, rt << 1) : qry(mid + 1, r, x, rt << 1 | 1);
}
vector<int> g[maxn];
int sz[maxn], son[maxn], d[maxn], fa[maxn];
void dfs(int u) {
  sz[u] = 1;
  for (int v : g[u])
    if (v ^ fa[u]) {
      fa[v] = u, d[v] = d[u] + 1, dfs(v), sz[u] += sz[v];
      if (sz[v] > sz[son[u]]) son[u] = v;
    }
}
int top[maxn], dfn[maxn], idx = 0;
void dfs(int u, int t) {
  dfn[u] = ++idx, top[u] = t;
  if (son[u]) dfs(son[u], t);
  for (int v : g[u])
    if (v ^ fa[u] && v ^ son[u]) dfs(v, v);
}
vector<pii> v, vec;
void swap(int& x, int& y) { x ^= y ^= x ^= y; }
void upd(int x, int y, int c) {
  v.clear(), vec.clear();
  while (top[x] ^ top[y]) {
    if (d[top[x]] < d[top[y]]) swap(x, y);
    v.push_back({ dfn[top[x]], dfn[x] });
    x = fa[top[x]];
  }
  if (d[x] > d[y]) swap(x, y);
  v.push_back({ dfn[x], dfn[y] });
  sort(v);
  int las = 1;
  for (pii x : v) {
    if (x.first > las) vec.push_back({ las, x.first - 1 });
    las = x.second + 1;
  }
  if (las <= n) vec.push_back({ las, n });
  for (pii x : vec) upd(x.first, x.second, 1, n, 1, c);
}
void erase(int x, int y, int c) {
  v.clear(), vec.clear();
  while (top[x] ^ top[y]) {
    if (d[top[x]] < d[top[y]]) swap(x, y);
    v.push_back({ dfn[top[x]], dfn[x] });
    x = fa[top[x]];
  }
  if (d[x] > d[y]) swap(x, y);
  v.push_back({ dfn[x], dfn[y] });
  sort(v);
  int las = 1;
  for (pii x : v) {
    if (x.first > las) vec.push_back({ las, x.first - 1 });
    las = x.second + 1;
  }
  if (las <= n) vec.push_back({ las, n });
  for (pii x : vec) erase(x.first, x.second, 1, n, 1, c);
}
const int maxm = 2e5 + 52;
int A[maxm], B[maxm], V[maxm];
signed main() {
#ifdef _WIN64
  freopen("testdata.in", "r", stdin);
#else
  ios_base ::sync_with_stdio(false);
  cin.tie(nullptr), cout.tie(nullptr);
#endif
  // code begin.
  in >> n >> m;
  rep(i, 2, n) {
    int u, v;
    in >> u >> v, g[u].pb(v), g[v].pb(u);
  }
  dfs(1), dfs(1, 1);
  rep(i, 1, m) {
    int op;
    in >> op;
    if (op == 0) {
      int x, y, c;
      in >> x >> y >> c;
      upd(x, y, c);
      A[i] = x, B[i] = y, V[i] = c;
    }
    if (op == 1) {
      int t;
      in >> t, erase(A[t], B[t], V[t]);
    }
    if (op == 2) {
      int u;
      in >> u, ans = -1, qry(1, n, dfn[u], 1);
      out << ans << '\n';
    }
  }
  return 0;
  // code end.
}