tpl_treap.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
 
# ifndef TPL_TREAP_H
# define TPL_TREAP_H
 
# include <gsl/gsl_rng.h>
# include <ahFunction.H>
# include <tpl_binNodeUtils.H>
# include <treapNode.H>
# include <tpl_binTreeOps.H>
# include <ah-errors.H>
# include <ah-concepts.H>
 
using namespace Aleph;
 
namespace Aleph
{
  template <template <typename> class NodeType, typename Key, class Compare>
    requires StrictWeakOrder<Compare, Key>
  class Gen_Treap
  {
  public:
    using Node = NodeType<Key>; 
 
  private:
    Node head;
    Node *head_ptr;
    Node *& tree_root;
    gsl_rng *r;
    Compare cmp;
 
    void init(const unsigned int seed)
    {
      PRIO(head_ptr) = Min_Priority;
      r = gsl_rng_alloc(gsl_rng_mt19937);
 
      ah_bad_alloc_if(r == nullptr);
 
      gsl_rng_set(r, seed % gsl_rng_max(r));
    }
 
  public:
    void set_seed(const unsigned long seed) noexcept { gsl_rng_set(r, seed); }
 
    void swap(Gen_Treap & tree) noexcept
    {
      std::swap(tree_root, tree.tree_root);
      std::swap(cmp, tree.cmp);
      std::swap(r, tree.r);
    }
 
    Compare &key_comp() noexcept { return cmp; }
 
    Compare &get_compare() noexcept { return key_comp(); }
 
    Gen_Treap(const unsigned long seed, const Compare & __cmp = Compare())
      : head_ptr(&head), tree_root(RLINK(head_ptr)), r(nullptr), cmp(__cmp)
    {
      init(seed);
    }
 
    Gen_Treap(const Compare & cmp = Compare())
      : Gen_Treap(time(nullptr), cmp)
    { /* empty */
    }
 
    ~Gen_Treap()
    {
      if (r != nullptr)
        gsl_rng_free(r);
    }
 
    gsl_rng * gsl_rng_object() noexcept { return r; }
 
    Node *&getRoot() noexcept { return tree_root; }
 
    Node * search(const Key & key) const noexcept
    {
      Node *ret_val = searchInBinTree(tree_root, key, cmp);
      return ret_val == Node::NullPtr ? nullptr : ret_val;
    }
 
  private:
    Node * insert(Node *root, Node *p) noexcept
    {
      if (root == Node::NullPtr)
        return p;
 
      const Key & pk = KEY(p);
      const Key & rk = KEY(root);
      Node *insertion_result = nullptr;
      if (cmp(pk, rk))
        {
          insertion_result = insert(LLINK(root), p);
          if (insertion_result == Node::NullPtr)
            return Node::NullPtr;
 
          LLINK(root) = insertion_result;
          if (PRIO(insertion_result) < PRIO(root))
            return rotate_to_right(root);
          return root;
        }
      if (cmp(rk, pk))
        {
          insertion_result = insert(RLINK(root), p);
          if (insertion_result == Node::NullPtr)
            return Node::NullPtr;
 
          RLINK(root) = insertion_result;
          if (PRIO(insertion_result) < PRIO(root))
            return rotate_to_left(root);
          return root;
        }
 
      return Node::NullPtr;
    }
 
    Node * search_or_insert(Node *& root, Node *p) noexcept
    {
      if (root == Node::NullPtr)
        return root = p;
 
      const Key & pk = KEY(p);
      const Key & rk = KEY(root);
      if (cmp(pk, rk))
        {
          Node *ret = search_or_insert(LLINK(root), p);
          if (ret == p) // p was inserted?
            if (PRIO(LLINK(root)) < PRIO(root))
              root = rotate_to_right(root);
 
          return ret;
        }
      if (cmp(rk, pk))
        {
          Node *ret = search_or_insert(RLINK(root), p);
          if (ret == p) // p was inserted?
            if (PRIO(RLINK(root)) < PRIO(root))
              root = rotate_to_left(root);
 
          return ret;
        }
 
      return root;
    }
 
    Node * insert_dup(Node *root, Node *p) noexcept
    {
      if (root == Node::NullPtr)
        return p;
 
      const Key & pk = KEY(p);
      const Key & rk = KEY(root);
      if (cmp(pk, rk))
        {
          if (Node *result = LLINK(root) = insert_dup(LLINK(root), p); PRIO(result) < PRIO(root))
            return rotate_to_right(root);
          return root;
        }
      if (Node *result = RLINK(root) = insert_dup(RLINK(root), p); PRIO(result) < PRIO(root))
        return rotate_to_left(root);
      return root;
    }
 
  public:
    Node * insert(Node *p) noexcept
    {
      assert(p != Node::NullPtr);
 
      PRIO(p) = gsl_rng_get(r); // Priority Random Selection
      Node *result = insert(tree_root, p);
      if (result == Node::NullPtr)
        return nullptr;
 
      tree_root = result;
 
      return p;
    }
 
    Node * search_or_insert(Node *p) noexcept
    {
      assert(p != Node::NullPtr);
 
      PRIO(p) = gsl_rng_get(r); // Priority Random Selection
 
      return search_or_insert(tree_root, p);
    }
 
    Node * insert_dup(Node *p) noexcept
    {
      assert(p != Node::NullPtr);
 
      PRIO(p) = gsl_rng_get(r); // Priority Random Selection
      tree_root = insert_dup(tree_root, p);
 
      return p;
    }
 
    bool verify() const noexcept { return is_treap(tree_root); }
 
    Node * remove(const Key & key) noexcept
    {
      Node **pp = &RLINK(head_ptr);
      Node *p = tree_root;
 
      while (p != Node::NullPtr) // descender buscando la clave
        {
          const Key & pk = KEY(p);
          if (cmp(key, pk))
            {
              pp = &LLINK(p);
              p = LLINK(p);
            }
          else if (cmp(pk, key))
            {
              pp = &RLINK(p);
              p = RLINK(p);
            }
          else
            break; //found!
        }
 
      if (p == Node::NullPtr)
        return nullptr; // Key was not found
 
      // rotate p until it becomes a leaf
      while (not (LLINK(p) == Node::NullPtr and RLINK(p) == Node::NullPtr))
        if (PRIO(LLINK(p)) < PRIO(RLINK(p)))
          {
            *pp = rotate_to_right(p);
            pp = &RLINK(*pp);
          }
        else
          {
            *pp = rotate_to_left(p);
            pp = &LLINK(*pp);
          }
 
      *pp = Node::NullPtr;
 
      p->reset();
 
      return p;
    }
 
  private:
    static Node * join_exclusive(Node *t1, Node *t2) noexcept
    {
      if (t1 == Node::NullPtr)
        return t2;
 
      if (t2 == Node::NullPtr)
        return t1;
 
      if (PRIO(t1) < PRIO(t2))
        {
          RLINK(t1) = join_exclusive(RLINK(t1), t2);
          return t1;
        }
      LLINK(t2) = join_exclusive(t1, LLINK(t2));
      return t2;
    }
 
    Node * remove(Node *& root, const Key & key) noexcept
    {
      if (root == Node::NullPtr)
        return Node::NullPtr;
 
      const Key & rk = KEY(root);
      if (cmp(key, rk))
        return remove(LLINK(root), key);
      if (cmp(rk, key))
        return remove(RLINK(root), key);
 
      Node *ret = root; // key found!
      root = join_exclusive(LLINK(root), RLINK(root));
      ret->reset();
 
      return ret;
    }
 
    void join_dup(Node *& t1, Node *t2) noexcept
    {
      if (t2 == Node::NullPtr)
        return;
 
      Node *l = LLINK(t2), *r = RLINK(t2);
      t2->reset();
      t1 = insert_dup(t1, t2);
      join_dup(t1, l);
      join_dup(t1, r);
    }
 
    void join(Node *& t1, Node *t2, Node *& dup) noexcept
    {
      if (t2 == Node::NullPtr)
        return;
 
      Node *l = LLINK(t2), *r = RLINK(t2);
      t2->reset();
    ins:
      Node *ret = insert(t1, t2);
      if (ret == Node::NullPtr)
        {
          dup = insert_dup(dup, remove(t1, KEY(t2)));
          goto ins;
        }
 
      t1 = ret;
      join(t1, l, dup);
      join(t1, r, dup);
    }
 
  public:
    void join(Gen_Treap & t, Gen_Treap & dup) noexcept
    {
      join(tree_root, t.tree_root, dup.tree_root);
      t.tree_root = Node::NullPtr;
    }
 
    void join_dup(Gen_Treap & t) noexcept
    {
      join_dup(tree_root, t.tree_root);
      t.tree_root = Node::NullPtr;
    }
 
    void join_exclusive(Gen_Treap & t) noexcept
    {
      tree_root = join_exclusive(tree_root, t.tree_root);
      t.tree_root = Node::NullPtr;
    }
 
    bool split_key(const Key & key, Gen_Treap & t1, Gen_Treap & t2)
    {
      return split_key_rec(tree_root, key, t1.getRoot(), t2.getRoot());
    }
 
    void split_key_dup(const Key & key, Gen_Treap & t1, Gen_Treap & t2)
    {
      split_key_dup_rec(tree_root, key, t1.getRoot(), t2.getRoot());
    }
 
    struct Iterator : public BinNodeInfixIterator<Node>
    {
      Iterator() noexcept = default;
      Iterator(Gen_Treap & t) : BinNodeInfixIterator<Node>(t.getRoot()) {}
    };
  };
 
  template <typename Key, class Compare = Aleph::less<Key>>
    requires StrictWeakOrder<Compare, Key>
  struct Treap : public Gen_Treap<TreapNode, Key, Compare>
  {
    using Base = Gen_Treap<TreapNode, Key, Compare>;
    using Base::Base;
  };
 
 
  template <typename Key, class Compare = Aleph::less<Key>>
    requires StrictWeakOrder<Compare, Key>
  struct Treap_Vtl : public Gen_Treap<TreapNodeVtl, Key, Compare>
  {
    using Base = Gen_Treap<TreapNodeVtl, Key, Compare>;
    using Base::Base;
  };
} // end namespace Aleph
# endif // TPL_TREAP_H