structure/bbst/persistent-red-black-tree.hpp

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• Last update: 2026-08-10 15:44:16+00:00
• Include: #include "structure/bbst/persistent-red-black-tree.hpp"

Depends on

• other/vector-pool.hpp
• Red Black Tree (赤黒木) (structure/bbst/red-black-tree.hpp)

Code

#pragma once

#include <cstddef>

#include "red-black-tree.hpp"

template <typename Monoid, typename F, std::size_t FULL = 1000>
struct PersistentRedBlackTree : RedBlackTree<Monoid, F> {
  using RBT = RedBlackTree<Monoid, F>;
  using RBT::RedBlackTree;
  using Node = typename RBT::Node;

 private:
  Node* clone(Node* t) override { return &(*RBT::pool.alloc() = *t); }

 public:
  Node* rebuild(Node* r) {
    auto ret = RBT::dump(r);
    RBT::pool.clear();
    return RBT::build(ret);
  }

  bool almost_full() const { return this->pool.ptr < FULL; }
};

#line 2 "structure/bbst/persistent-red-black-tree.hpp"

#include <cstddef>

#line 2 "structure/bbst/red-black-tree.hpp"

#line 4 "structure/bbst/red-black-tree.hpp"
#include <iterator>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#line 2 "other/vector-pool.hpp"

#line 4 "other/vector-pool.hpp"

template <class T>
struct VectorPool {
  std::vector<T> pool;
  std::vector<T*> stock;
  int ptr;

  VectorPool() = default;

  VectorPool(int sz) : pool(sz), stock(sz) {}

  inline T* alloc() { return stock[--ptr]; }

  inline void free(T* t) { stock[ptr++] = t; }

  void clear() {
    ptr = (int)pool.size();
    for (int i = 0; i < (int)pool.size(); i++) stock[i] = &pool[i];
  }
};
#line 11 "structure/bbst/red-black-tree.hpp"

/**
 * @brief Red-Black-Tree(赤黒木)
 *
 */
template <typename Monoid, typename F>
struct RedBlackTree {
 public:
  enum COLOR { BLACK, RED };

  struct Node {
    Node *l, *r;
    COLOR color;
    int level, cnt;
    Monoid key, sum;

    Node() {}

    Node(const Monoid& k)
        : key(k),
          sum(k),
          l(nullptr),
          r(nullptr),
          color(BLACK),
          level(0),
          cnt(1) {}

    Node(Node* l, Node* r, const Monoid& k) : key(k), color(RED), l(l), r(r) {}

    bool is_leaf() const { return l == nullptr; }
  };

 private:
  inline Node* alloc(Node* l, Node* r) {
    auto t = &(*pool.alloc() = Node(l, r, M1));
    return update(t);
  }

  virtual Node* clone(Node* t) { return t; }

  Node* rotate(Node* t, bool b) {
    t = clone(t);
    Node* s;
    if (b) {
      s = clone(t->l);
      t->l = s->r;
      s->r = t;
    } else {
      s = clone(t->r);
      t->r = s->l;
      s->l = t;
    }
    update(t);
    return update(s);
  }

  Node* submerge(Node* l, Node* r) {
    if (l->level == r->level) {
      if (l->color != r->color) {
        if (l->color == RED) {
          l = clone(l);
          l->color = BLACK;
        } else {
          r = clone(r);
          r->color = BLACK;
        }
      }
      return alloc(l, r);
    } else if (l->level < r->level) {
      r = clone(r);
      Node* c = (r->l = submerge(l, r->l));
      if (r->color == BLACK && c->color == RED && c->l && c->l->color == RED) {
        r->color = RED;
        c->color = BLACK;
        if (r->r->color == BLACK) return rotate(r, true);
        r->r->color = BLACK;
      }
      return update(r);
    } else {
      l = clone(l);
      Node* c = (l->r = submerge(l->r, r));
      if (l->color == BLACK && c->color == RED && c->r && c->r->color == RED) {
        l->color = RED;
        c->color = BLACK;
        if (l->l->color == BLACK) return rotate(l, false);
        l->l->color = BLACK;
      }
      return update(l);
    }
  }

  Node* build(int l, int r, const std::vector<Monoid>& v) {
    if (l + 1 >= r) return alloc(v[l]);
    return merge(build(l, (l + r) >> 1, v), build((l + r) >> 1, r, v));
  }

  Node* update(Node* t) {
    t->cnt = count(t->l) + count(t->r) + (!t->l || !t->r);
    t->level = t->l ? t->l->level + (t->l->color == BLACK) : 0;
    t->sum = f(f(sum(t->l), t->key), sum(t->r));
    return t;
  }

  void dump(Node* r, typename std::vector<Monoid>::iterator& it) {
    if (r->is_leaf()) {
      *it++ = r->key;
      return;
    }
    dump(r->l, it);
    dump(r->r, it);
  }

  Node* merge(Node* l) { return l; }

  Monoid query(Node* t, int a, int b, int l, int r) {
    if (r <= a || b <= l) return M1;
    if (a <= l && r <= b) return t->sum;
    return f(query(t->l, a, b, l, l + count(t->l)),
             query(t->r, a, b, r - count(t->r), r));
  }

 public:
  VectorPool<Node> pool;
  const F f;
  const Monoid M1;

  RedBlackTree(int sz, const F& f, const Monoid& M1) : pool(sz), M1(M1), f(f) {
    pool.clear();
  }

  inline Node* alloc(const Monoid& key) { return &(*pool.alloc() = Node(key)); }

  inline int count(const Node* t) { return t ? t->cnt : 0; }

  inline const Monoid& sum(const Node* t) { return t ? t->sum : M1; }

  std::pair<Node*, Node*> split(Node* t, int k) {
    if (!t) return {nullptr, nullptr};
    if (k == 0) return {nullptr, t};
    if (k >= count(t)) return {t, nullptr};
    t = clone(t);
    Node *l = t->l, *r = t->r;
    pool.free(t);
    if (k < count(l)) {
      auto pp = split(l, k);
      return {pp.first, merge(pp.second, r)};
    }
    if (k > count(l)) {
      auto pp = split(r, k - count(l));
      return {merge(l, pp.first), pp.second};
    }
    return {l, r};
  }

  std::tuple<Node*, Node*, Node*> split3(Node* t, int a, int b) {
    auto x = split(t, a);
    auto y = split(x.second, b - a);
    return std::make_tuple(x.first, y.first, y.second);
  }

  template <typename... Args>
  Node* merge(Node* l, Args... rest) {
    Node* r = merge(rest...);
    if (!l || !r) return l ? l : r;
    Node* c = submerge(l, r);
    c->color = BLACK;
    return c;
  }

  Node* build(const std::vector<Monoid>& v) {
    return build(0, (int)v.size(), v);
  }

  std::vector<Monoid> dump(Node* r) {
    std::vector<Monoid> v((std::size_t)count(r));
    auto it = std::begin(v);
    dump(r, it);
    return v;
  }

  std::string to_string(Node* r) {
    auto s = dump(r);
    std::string ret;
    for (int i = 0; i < s.size(); i++) {
      ret += std::to_string(s[i]);
      ret += ", ";
    }
    return ret;
  }

  void insert(Node*& t, int k, const Monoid& v) {
    auto x = split(t, k);
    t = merge(merge(x.first, alloc(v)), x.second);
  }

  Monoid erase(Node*& t, int k) {
    auto x = split(t, k);
    auto y = split(x.second, 1);
    auto v = y.first->key;
    pool.free(y.first);
    t = merge(x.first, y.second);
    return v;
  }

  Monoid query(Node* t, int a, int b) { return query(t, a, b, 0, count(t)); }

  void set_element(Node*& t, int k, const Monoid& x) {
    t = clone(t);
    if (t->is_leaf()) {
      t->key = t->sum = x;
      return;
    }
    if (k < count(t->l))
      set_element(t->l, k, x);
    else
      set_element(t->r, k - count(t->l), x);
    t = update(t);
  }

  void push_front(Node*& t, const Monoid& v) { t = merge(alloc(v), t); }

  void push_back(Node*& t, const Monoid& v) { t = merge(t, alloc(v)); }

  Monoid pop_front(Node*& t) {
    auto ret = split(t, 1);
    t = ret.second;
    return ret.first->key;
  }

  Monoid pop_back(Node*& t) {
    auto ret = split(t, count(t) - 1);
    t = ret.first;
    return ret.second->key;
  }
};
#line 6 "structure/bbst/persistent-red-black-tree.hpp"

template <typename Monoid, typename F, std::size_t FULL = 1000>
struct PersistentRedBlackTree : RedBlackTree<Monoid, F> {
  using RBT = RedBlackTree<Monoid, F>;
  using RBT::RedBlackTree;
  using Node = typename RBT::Node;

 private:
  Node* clone(Node* t) override { return &(*RBT::pool.alloc() = *t); }

 public:
  Node* rebuild(Node* r) {
    auto ret = RBT::dump(r);
    RBT::pool.clear();
    return RBT::build(ret);
  }

  bool almost_full() const { return this->pool.ptr < FULL; }
};

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