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// -*- C++ -*-

// Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the terms

// of the GNU General Public License as published by the Free Software

// Foundation; either version 3, or (at your option) any later

// version.

// This library is distributed in the hope that it will be useful, but

// WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

// General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with this library; see the file COPYING3.  If not see

// <http://www.gnu.org/licenses/>.

// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software

// is hereby granted without fee, provided that the above copyright

// notice appears in all copies, and that both that copyright notice

// and this permission notice appear in supporting documentation. None

// of the above authors, nor IBM Haifa Research Laboratories, make any

// representation about the suitability of this software for any

// purpose. It is provided "as is" without express or implied

// warranty.

/**

 * @file tree_order_statistics_example.cpp

 * An example showing how to use functors for order-statistics

 *    in tree-based containers.

 */

/**

 * In some cases tree structure can be used for various purposes asides

 *    from storing entries by key order.

 *    This example shows how a tree-based container can be used for

 *    order-statistics, i.e., for determining the order of each key

 *     in the (ordered) sequence of keys stored within the container object.

 */

#include <cassert>

#include <ext/pb_ds/assoc_container.hpp>

#include <ext/pb_ds/tree_policy.hpp>

using namespace std;

using namespace __gnu_pbds;

// A red-black tree table storing ints and their order

// statistics. Note that since the tree uses

// tree_order_statistics_node_update as its update policy, then it

// includes its methods by_order and order_of_key.

typedef

tree<

  int,

  null_type,

  less<int>,

  rb_tree_tag,

  // This policy updates nodes' metadata for order statistics.

  tree_order_statistics_node_update>

set_t;

int main()

{

  // Insert some entries into s.

  set_t s;

  s.insert(12);

  s.insert(505);

  s.insert(30);

  s.insert(1000);

  s.insert(10000);

  s.insert(100);

  // The order of the keys should be: 12, 30, 100, 505, 1000, 10000.

  assert(*s.find_by_order(0) == 12);

  assert(*s.find_by_order(1) == 30);

  assert(*s.find_by_order(2) == 100);

  assert(*s.find_by_order(3) == 505);

  assert(*s.find_by_order(4) == 1000);

  assert(*s.find_by_order(5) == 10000);

  assert(s.find_by_order(6) == s.end());

  // The order of the keys should be: 12, 30, 100, 505, 1000, 10000.

  assert(s.order_of_key(10) == 0);

  assert(s.order_of_key(12) == 0);

  assert(s.order_of_key(15) == 1);

  assert(s.order_of_key(30) == 1);

  assert(s.order_of_key(99) == 2);

  assert(s.order_of_key(100) == 2);

  assert(s.order_of_key(505) == 3);

  assert(s.order_of_key(1000) == 4);

  assert(s.order_of_key(10000) == 5);

  assert(s.order_of_key(9999999) == 6);

  // Erase an entry.

  s.erase(30);

  // The order of the keys should be: 12, 100, 505, 1000, 10000.

  assert(*s.find_by_order(0) == 12);

  assert(*s.find_by_order(1) == 100);

  assert(*s.find_by_order(2) == 505);

  assert(*s.find_by_order(3) == 1000);

  assert(*s.find_by_order(4) == 10000);

  assert(s.find_by_order(5) == s.end());

  // The order of the keys should be: 12, 100, 505, 1000, 10000.

  assert(s.order_of_key(10) == 0);

  assert(s.order_of_key(12) == 0);

  assert(s.order_of_key(100) == 1);

  assert(s.order_of_key(505) == 2);

  assert(s.order_of_key(707) == 3);

  assert(s.order_of_key(1000) == 3);

  assert(s.order_of_key(1001) == 4);

  assert(s.order_of_key(10000) == 4);

  assert(s.order_of_key(100000) == 5);

  assert(s.order_of_key(9999999) == 5);

  return 0;

}