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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2019 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 priority_queue_split_join_example.cpp
  34  * A basic example showing how to split and join priority queues.
  35  */
  36
  37 /**
  38  * This example shows how to split and join priority queues.
  39  */
  40
  41 #include <functional>
  42 #include <iostream>
  43 #include <cassert>
  44 #include <ext/pb_ds/priority_queue.hpp>
  45
  46 using namespace std;
  47 using namespace __gnu_pbds;
  48
  49 int
  50 main()
  51 {
  52   // Two priority queue objects.
  53   __gnu_pbds::priority_queue<int> even_p, odd_p;
  54
  55   // First we insert some values: even ones into even_p, and odd ones
  56   // into odd_p.
  57   for (size_t i = 0; i < 10; ++i)
  58     {
  59       even_p.push(2*  i);
  60       odd_p.push(2*  i + 1);
  61     }
  62
  63   // Check that each one contains the appropriate 10 values.
  64   assert(even_p.size() == 10);
  65   assert(even_p.top() == 18);
  66
  67   // Print out the values.
  68   cout << "Initial values in even priority queue:" << endl;
  69   __gnu_pbds::priority_queue<int>::const_iterator it;
  70   for (it = even_p.begin(); it != even_p.end(); ++it)
  71     cout <<* it << endl;
  72
  73   assert(odd_p.size() == 10);
  74   assert(odd_p.top() == 19);
  75
  76   // Print out the values.
  77   cout << "Initial values in odd priority queue:" << endl;
  78   for (it = odd_p.begin(); it != odd_p.end(); ++it)
  79     cout <<* it << endl;
  80
  81   // Now join the queues.
  82   even_p.join(odd_p);
  83
  84   // Check that each one contains the appropriate values.
  85
  86   assert(even_p.size() == 20);
  87   assert(even_p.top() == 19);
  88
  89   // Print out the values.
  90   cout << "After-join values in even priority queue:" << endl;
  91   for (it = even_p.begin(); it != even_p.end(); ++it)
  92     cout <<* it << endl;
  93
  94   assert(odd_p.size() == 0);
  95
  96   // Print out the values.
  97   cout << "After-join values in odd priority queue:" << endl;
  98   for (it = odd_p.begin(); it != odd_p.end(); ++it)
  99     cout <<* it << endl;
 100
 101   // Now split the queues.
 102   even_p.split(bind2nd(modulus<int>(), 2), odd_p);
 103
 104   // Check that each one contains the appropriate 10 values.
 105
 106   assert(even_p.size() == 10);
 107   assert(even_p.top() == 18);
 108
 109   // Print out the values.
 110   cout << "After-split values in even priority queue:" << endl;
 111   for (it = even_p.begin(); it != even_p.end(); ++it)
 112     cout <<* it << endl;
 113
 114   assert(odd_p.size() == 10);
 115   assert(odd_p.top() == 19);
 116
 117   // Print out the values.
 118   cout << "After-split values in odd priority queue:" << endl;
 119   for (it = odd_p.begin(); it != odd_p.end(); ++it)
 120     cout <<* it << endl;
 121
 122   return 0;
 123 }
 124