libstdc++-v3/testsuite/ext/pb_ds/example/tree_order_statistics_join.cc

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2024 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the terms
   7 // of the GNU General Public License as published by the Free Software
   8 // Foundation; either version 3, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20
  21 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  22
  23 // Permission to use, copy, modify, sell, and distribute this software
  24 // is hereby granted without fee, provided that the above copyright
  25 // notice appears in all copies, and that both that copyright notice
  26 // and this permission notice appear in supporting documentation. None
  27 // of the above authors, nor IBM Haifa Research Laboratories, make any
  28 // representation about the suitability of this software for any
  29 // purpose. It is provided "as is" without express or implied
  30 // warranty.
  31
  32 /**
  33  * @file tree_order_statistics_join_example.cpp
  34  * An example showing how to augment a splay tree to support order statistics.
  35  */
  36
  37 // This example shows how join operations still maintain node
  38 // invariants. Specifically, it shows how the objects of containers
  39 // supporting order statistics can be joined into an object supporting
  40 // order statistics.
  41 // While the example does not show this, the same holds for split operations.
  42
  43 #include <cassert>
  44 #include <ext/pb_ds/assoc_container.hpp>
  45 #include <ext/pb_ds/tree_policy.hpp>
  46
  47 using namespace std;
  48 using namespace __gnu_pbds;
  49
  50 // A splay tree table mapping ints to chars and storing the ints order
  51 // statistics.
  52 typedef
  53 tree<int, char, less<int>,
  54      splay_tree_tag,
  55      tree_order_statistics_node_update>
  56 tree_map_t;
  57
  58 int main()
  59 {
  60   // Insert some entries into s0.
  61   tree_map_t s0;
  62   s0.insert(make_pair(12, 'a'));
  63   s0.insert(make_pair(505, 'b'));
  64   s0.insert(make_pair(30, 'c'));
  65
  66   // The order of the keys should be: 12, 30, 505.
  67   assert(s0.find_by_order(0)->first == 12);
  68   assert(s0.find_by_order(1)->first == 30);
  69   assert(s0.find_by_order(2)->first == 505);
  70
  71   // Insert some entries into s1.
  72   tree_map_t s1;
  73   s1.insert(make_pair(506, 'a'));
  74   s1.insert(make_pair(1222, 'b'));
  75   s1.insert(make_pair(3004, 'a'));
  76
  77   // Now join s0 and s1.
  78   s0.join(s1);
  79
  80   // The order of the keys should be: 12, 30, 505, 506, 1222, 3004.
  81   assert(s0.find_by_order(0)->first == 12);
  82   assert(s0.find_by_order(1)->first == 30);
  83   assert(s0.find_by_order(2)->first == 505);
  84   assert(s0.find_by_order(3)->first == 506);
  85   assert(s0.find_by_order(4)->first == 1222);
  86   assert(s0.find_by_order(5)->first == 3004);
  87
  88   return 0;
  89 }
  90