P3380 【模板】二逼平衡树（树套树）

https://www.luogu.com.cn/record/81169175

Luogu/P3380/P3380.cpp

@@ -0,0 +1,308 @@
+#include <iostream>
+#include <chrono>
+#include <limits>
+#include <random>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 5e4 + 5;
+
+class Treap {
+  private:
+    struct node {
+        node *lchild, *rchild;
+        int size, value, key;
+
+        node()
+            : lchild(nullptr), rchild(nullptr), size(0), value(0), key(rand()) {}
+
+        node(int _value)
+            : lchild(nullptr), rchild(nullptr), size(1), value(_value), key(rand()) {}
+
+        ~node() {
+            delete lchild;
+            delete rchild;
+        }
+
+        inline void pushup() {
+            size = 1;
+            if (lchild != nullptr) size += lchild->size;
+            if (rchild != nullptr) size += rchild->size;
+        }
+    } * root;
+
+    inline int getNodeSize(node *node) {
+        return node == nullptr ? 0 : node->size;
+    }
+
+    std::pair<node *, node *> split(node *p, int k) {
+        if (p == nullptr) return std::make_pair(nullptr, nullptr);
+
+        if (k <= getNodeSize(p->lchild)) {
+            auto o = split(p->lchild, k);
+            p->lchild = o.second;
+            p->pushup();
+            o.second = p;
+
+            return o;
+        }
+
+        auto o = split(p->rchild, k - getNodeSize(p->lchild) - 1);
+        p->rchild = o.first;
+        p->pushup();
+        o.first = p;
+
+        return o;
+    }
+
+    std::pair<node *, node *> splitByValue(node *p, int value) {
+        if (p == nullptr) return std::make_pair(nullptr, nullptr);
+
+        if (p->value < value) {
+            auto o = splitByValue(p->rchild, value);
+            p->rchild = o.first;
+            p->pushup();
+            o.first = p;
+
+            return o;
+        }
+
+        auto o = splitByValue(p->lchild, value);
+        p->lchild = o.second;
+        p->pushup();
+        o.second = p;
+
+        return o;
+    }
+
+    node *merge(node *x, node *y) {
+        if (x == nullptr) return y;
+        if (y == nullptr) return x;
+
+        if (x->key > y->key) {
+            x->rchild = merge(x->rchild, y);
+            x->pushup();
+            return x;
+        }
+
+        y->lchild = merge(x, y->lchild);
+        y->pushup();
+        return y;
+    }
+
+  public:
+    Treap()
+        : root(nullptr) {}
+
+    ~Treap() {
+        delete root;
+    }
+
+    inline void insert(int value) {
+        auto o = splitByValue(root, value);
+        o.first = merge(o.first, new node(value));
+        root = merge(o.first, o.second);
+    }
+
+    inline void erase(int value) {
+        auto o = splitByValue(root, value);
+        auto t = split(o.second, 1);
+
+        if (t.first->value == value) {
+            delete t.first;
+        }
+
+        root = merge(o.first, t.second);
+    }
+
+    inline int rank(int value) {
+        auto x = splitByValue(root, value);
+        int r = getNodeSize(x.first) + 1;
+        root = merge(x.first, x.second);
+        return r;
+    }
+
+    inline int kth(int k) {
+        auto x = split(root, k - 1);
+        auto y = split(x.second, 1);
+        Treap::node *o = y.first;
+        root = merge(x.first, merge(y.first, y.second));
+        return o == nullptr ? 0 : o->value;
+    }
+
+    inline int pre(int x) {
+        int k = rank(x) - 1;
+        return k > 0
+                 ? kth(k)
+                 : std::numeric_limits<int>::min() + 1;
+    }
+
+    inline int suc(int x) {
+        int k = rank(x + 1);
+        return k > getNodeSize(root)
+                 ? std::numeric_limits<int>::max()
+                 : kth(k);
+    }
+};
+
+struct node : Treap {
+    int l, r;
+    node *lchild, *rchild;
+
+    node()
+        : l(0), r(0), lchild(nullptr), rchild(nullptr) {}
+
+    node(const int &_l, const int &_r)
+        : l(_l), r(_r), lchild(nullptr), rchild(nullptr) {}
+
+    ~node() {
+        if (lchild != nullptr) delete lchild;
+        if (rchild != nullptr) delete rchild;
+    }
+} * root;
+
+int n, m, a[N];
+
+void build(node *&u, int l, int r) {
+    u = new node(l, r);
+
+    for (int i = l; i <= r; i++) {
+        u->insert(a[i]);
+    }
+
+    if (l == r) return;
+
+    int mid = (l + r) >> 1;
+
+    build(u->lchild, l, mid);
+    build(u->rchild, mid + 1, r);
+}
+
+int query_rank(node *u, int l, int r, int x) {
+    if (l <= u->l && u->r <= r) {
+        return u->rank(x) - 1;
+    }
+
+    int mid = (u->l + u->r) >> 1;
+    int res = 0;
+
+    if (l <= mid) res += query_rank(u->lchild, l, r, x);
+    if (r > mid) res += query_rank(u->rchild, l, r, x);
+
+    return res;
+}
+
+int query_kth(int _l, int _r, int k) {
+    int l = 0, r = 1e8, res = -1;
+
+    while (l <= r) {
+        int mid = (l + r + 1) >> 1;
+
+        if (query_rank(root, _l, _r, mid) + 1 <= k) {
+            l = mid + 1;
+            res = mid;
+        } else {
+            r = mid - 1;
+        }
+    }
+
+    return res;
+}
+
+void modify(node *u, int p, int x) {
+    u->erase(a[p]);
+    u->insert(x);
+
+    if (u->l == u->r) return;
+
+    int mid = (u->l + u->r) >> 1;
+
+    if (p <= mid) modify(u->lchild, p, x);
+    else modify(u->rchild, p, x);
+}
+
+int query_pre(node *u, int l, int r, int x) {
+    if (l <= u->l && u->r <= r) {
+        return u->pre(x);
+    }
+
+    int mid = (u->l + u->r) >> 1;
+    int res = std::numeric_limits<int>::min() + 1;
+
+    if (l <= mid) res = std::max(res, query_pre(u->lchild, l, r, x));
+    if (r > mid) res = std::max(res, query_pre(u->rchild, l, r, x));
+
+    return res;
+}
+
+int query_suc(node *u, int l, int r, int x) {
+    if (l <= u->l && u->r <= r) {
+        return u->suc(x);
+    }
+
+    int mid = (u->l + u->r) >> 1;
+    int res = std::numeric_limits<int>::max();
+
+    if (l <= mid) res = std::min(res, query_suc(u->lchild, l, r, x));
+    if (r > mid) res = std::min(res, query_suc(u->rchild, l, r, x));
+
+    return res;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    build(root, 1, n);
+
+    while (m--) {
+        int op;
+
+        cin >> op;
+
+        if (op == 1) {
+            int l, r, x;
+
+            cin >> l >> r >> x;
+
+            cout << query_rank(root, l, r, x) + 1 << endl;
+        } else if (op == 2) {
+            int l, r, k;
+
+            cin >> l >> r >> k;
+
+            cout << query_kth(l, r, k) << endl;
+        } else if (op == 3) {
+            int p, x;
+
+            cin >> p >> x;
+
+            modify(root, p, x);
+            a[p] = x;
+        } else if (op == 4) {
+            int l, r, x;
+
+            cin >> l >> r >> x;
+
+            cout << query_pre(root, l, r, x) << endl;
+        } else {  // op == 5
+            int l, r, x;
+
+            cin >> l >> r >> x;
+
+            cout << query_suc(root, l, r, x) << endl;
+        }
+    }
+
+    delete root;
+
+    return 0;
+}