P3250 [HNOI2016] 网络

https://www.luogu.com.cn/record/97824459

Luogu/P3250/P3250.cpp

@@ -0,0 +1,231 @@
+#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;
+}