writeBalance.C

Go to the documentation of this file.

 
/*
                          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.
*/
 
 
# include <iostream>
# include <fstream>
# include <tclap/CmdLine.h>
# include <aleph.H>
# include <tpl_dynArray.H>
# include <tpl_balanceXt.H>
 
using namespace Aleph;
using namespace std;
 
typedef BinNodeXt<int> Node;
 
// Output streams
ofstream outputb;
ofstream outputa;
 
void print_keyb(Node* p, int, int)
{
  outputb << p->get_key() << " ";
}
 
void print_keya(Node* p, int, int)
{
  outputa << p->get_key() << " ";
}
 
int main(int argc, char* argv[])
{
  try
    {
      TCLAP::CmdLine cmd(
        "Demonstrate BST balancing (DSW algorithm).\n"
        "Creates an unbalanced tree and shows the result of balancing.",
        ' ', "1.0");
 
      TCLAP::ValueArg<int> nArg("n", "count",
                                 "Number of elements",
                                 false, 10, "int");
      cmd.add(nArg);
 
      TCLAP::ValueArg<unsigned int> seedArg("s", "seed",
                                             "Random seed (0 = use time)",
                                             false, 0, "unsigned int");
      cmd.add(seedArg);
 
      cmd.parse(argc, argv);
 
      int n = nArg.getValue();
      unsigned int t = seedArg.getValue();
 
      if (n <= 0)
        {
          cerr << "Error: number of elements must be positive\n";
          return 1;
        }
 
      if (t == 0)
        t = time(nullptr);
 
      srand(t);
 
      cout << "=== BST Balancing Demo (median rotations) ===" << endl;
      cout << "Elements: " << n << ", Seed: " << t << endl << endl;
 
      // Open output files
      outputb.open("balance-before-aux.Tree", ios::out);
      outputa.open("balance-after-aux.Tree", ios::out);
 
      if (!outputb.is_open() || !outputa.is_open())
        {
          cerr << "Error: cannot open output files" << endl;
          return 1;
        }
 
      // Build ranked tree (will be unbalanced due to random insertion)
      Node* root = Node::NullPtr;
      int value;
 
      cout << "Building unbalanced BST with " << n << " elements..." << endl;
      for (int i = 0; i < n; i++)
        {
          while (true)
            {
              value = static_cast<int>(100.0 * n * rand() / (RAND_MAX + 1.0));
              if (searchInBinTree(root, value) == Node::NullPtr)
                break;
            }
          Node* p = new Node(value);
          insert_by_key_xt(root, p);
        }
 
      assert(check_rank_tree(root));
 
      int height_before = computeHeightRec(root);
      int node_count = root->getCount();
      cout << "Before balancing:" << endl;
      cout << "  Nodes: " << node_count << ", Height: " << height_before << endl;
      cout << "  Approx. optimal height would be: " << (static_cast<int>(log2(node_count)) + 1) << endl;
 
      // Write tree before balancing
      preOrderRec(root, &print_keyb);
      outputb << endl;
 
      // Balance the tree
      cout << endl << "Balancing tree by median selection + rotations..." << endl;
      root = balance_tree(root);
 
      assert(check_rank_tree(root));
 
      int height_after = computeHeightRec(root);
      cout << "After balancing:" << endl;
      cout << "  Nodes: " << root->getCount() << ", Height: " << height_after << endl;
      cout << "  Height reduction: " << (height_before - height_after) << " levels" << endl;
 
      // Write tree after balancing
      preOrderRec(root, &print_keya);
      outputa << endl;
 
      // Clean up
      outputb.close();
      outputa.close();
      destroyRec(root);
 
      cout << endl << "Generated files:" << endl;
      cout << "  - balance-before-aux.Tree (original unbalanced)" << endl;
      cout << "  - balance-after-aux.Tree (after balancing)" << endl;
    }
  catch (TCLAP::ArgException& e)
    {
      cerr << "Error: " << e.error() << " for arg " << e.argId() << endl;
      return 1;
    }
 
  return 0;
}