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OI-codes/Luogu/P3250/P3250.cpp

232 lines
4.1 KiB
C++

#include <iostream>
#include <algorithm>
#include <queue>
#include <tuple>
#include <utility>
#include <vector>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 1e5 + 5,
M = 2e5 + 5;
int n, m;
int cnt, dep[N], id[N], siz[N], fa[N], son[N], top[N];
std::vector<int> g[N];
std::tuple<int, int, int> tasks[M];
class Queue {
private:
std::priority_queue<int> q, r;
public:
Queue()
: q(), r() {}
int top() {
while (!q.empty() && !r.empty() && q.top() == r.top()) q.pop(), r.pop();
return q.empty() ? -1 : q.top();
}
void push(const int &val) {
q.push(val);
}
void erase(const int &val) {
r.push(val);
}
};
struct node : public Queue {
int l, r;
node(const int &_l = 0, const int &_r = 0)
: l(_l),
r(_r),
Queue() {}
} tr[N << 2];
void build(int u, int l, int r) {
tr[u] = node(l, r);
if (l == r) return;
int mid = (l + r) >> 1;
build(u << 1, l, mid);
build(u << 1 | 1, mid + 1, r);
}
int query(int u, int x) {
if (tr[u].l == tr[u].r) return tr[u].top();
int mid = (tr[u].l + tr[u].r) >> 1,
res = tr[u].top();
if (x <= mid) res = std::max(res, query(u << 1, x));
else res = std::max(res, query(u << 1 | 1, x));
return res;
}
void push(int u, int l, int r, int v) {
if (l <= tr[u].l && tr[u].r <= r) {
tr[u].push(v);
return;
}
int mid = (tr[u].l + tr[u].r) >> 1;
if (l <= mid) push(u << 1, l, r, v);
if (r > mid) push(u << 1 | 1, l, r, v);
}
void erase(int u, int l, int r, int v) {
if (l <= tr[u].l && tr[u].r <= r) {
tr[u].erase(v);
return;
}
int mid = (tr[u].l + tr[u].r) >> 1;
if (l <= mid) erase(u << 1, l, r, v);
if (r > mid) erase(u << 1 | 1, l, r, v);
}
void dfs1(int u, int f) {
dep[u] = dep[f] + 1;
fa[u] = f;
siz[u] = 1;
for (int v : g[u]) {
if (v == f) continue;
dfs1(v, u);
siz[u] += siz[v];
if (siz[son[u]] < siz[v]) son[u] = v;
}
}
void dfs2(int u, int t) {
id[u] = ++cnt;
top[u] = t;
if (!son[u]) return;
dfs2(son[u], t);
for (int v : g[u]) {
if (v == fa[u] || v == son[u]) continue;
dfs2(v, v);
}
}
void push_path(int u, int v, int val) {
std::vector<std::pair<int, int>> qs;
while (top[u] != top[v]) {
if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
qs.emplace_back(id[top[u]], id[u]);
u = fa[top[u]];
}
if (dep[u] < dep[v]) std::swap(u, v);
qs.emplace_back(id[v], id[u]);
std::sort(qs.begin(), qs.end());
int lst = 0;
for (auto o : qs) {
push(1, lst + 1, o.first - 1, val);
lst = o.second;
}
if (qs.back().second < n) {
push(1, qs.back().second + 1, n, val);
}
}
void erase_path(int u, int v, int val) {
std::vector<std::pair<int, int>> qs;
while (top[u] != top[v]) {
if (dep[top[u]] < dep[top[v]]) std::swap(u, v);
qs.emplace_back(id[top[u]], id[u]);
u = fa[top[u]];
}
if (dep[u] < dep[v]) std::swap(u, v);
qs.emplace_back(id[v], id[u]);
std::sort(qs.begin(), qs.end());
int lst = 0;
for (auto o : qs) {
erase(1, lst + 1, o.first - 1, val);
lst = o.second;
}
if (qs.back().second < n) {
erase(1, qs.back().second + 1, n, val);
}
}
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m;
for (int i = 1, u, v; i < n; i++) {
cin >> u >> v;
g[u].emplace_back(v);
g[v].emplace_back(u);
}
dfs1(1, 1);
dfs2(1, 1);
build(1, 1, n);
for (int i = 1, op; i <= m; i++) {
cin >> op;
if (op == 0) {
int a, b, v;
cin >> a >> b >> v;
tasks[i] = {a, b, v};
push_path(a, b, v);
} else if (op == 1) {
int t, a, b, v;
cin >> t;
std::tie(a, b, v) = tasks[t];
erase_path(a, b, v);
} else { // op == 2
int x;
cin >> x;
cout << query(1, id[x]) << endl;
}
}
return 0;
}