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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2021 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 basic_priority_queue_example.cpp
  34  * A basic example showing how to use priority queues.
  35  */
  36
  37 /**
  38  * This example shows how to use priority queues. It defines a
  39  * function performing a sequence of operations on
  40  * a generic container. It then calls this function with some containers.
  41  */
  42
  43 #include <cassert>
  44 #include <iostream>
  45 #include <ext/pb_ds/priority_queue.hpp>
  46
  47 using namespace std;
  48 using namespace __gnu_pbds;
  49
  50 // The following function performs a sequence of operations on a
  51 // priority queue object storing integers.
  52 template<class Cntnr>
  53 void
  54 some_op_sequence(Cntnr& r_c)
  55 {
  56   assert(r_c.empty());
  57   assert(r_c.size() == 0);
  58
  59   for (size_t i = 0; i < 10; ++i)
  60     r_c.push(i);
  61   cout << endl << "All values in the container:" << endl;
  62
  63   typedef typename Cntnr::const_iterator const_iterator;
  64   for (const_iterator it = r_c.begin(); it != r_c.end();  ++it)
  65     cout << *it << endl;
  66   assert(!r_c.empty());
  67   assert(r_c.size() == 10);
  68
  69   cout << "Popping all values: " << endl;
  70   while (!r_c.empty())
  71     {
  72       cout << r_c.top() << endl;
  73       r_c.pop();
  74     }
  75   assert(r_c.empty());
  76   assert(r_c.size() == 0);
  77
  78   cout << endl;
  79 }
  80
  81 int main()
  82 {
  83   {
  84     // Perform operations on a pairing-heap queue.
  85     cout << "Pairing heap" << endl;
  86     __gnu_pbds::priority_queue<int, less<int>, pairing_heap_tag> c;
  87     some_op_sequence(c);
  88   }
  89
  90   {
  91     // Perform operations on a binomial-heap queue.
  92     cout << "Binomial heap" << endl;
  93     __gnu_pbds::priority_queue<int, less<int>, binomial_heap_tag> c;
  94     some_op_sequence(c);
  95   }
  96
  97   {
  98     // Perform operations on a binomial-heap queue.
  99     cout << "Redundant-counter binomial heap" << endl;
 100     __gnu_pbds::priority_queue<int, less<int>, rc_binomial_heap_tag> c;
 101     some_op_sequence(c);
 102   }
 103
 104   {
 105     // Perform operations on a binomial-heap queue.
 106     cout << "Binary heap" << endl;
 107     __gnu_pbds::priority_queue<int, less<int>, binary_heap_tag> c;
 108     some_op_sequence(c);
 109   }
 110
 111   {
 112     // Perform operations on a thin-heap queue.
 113     cout << "Thin heap" << endl;
 114     __gnu_pbds::priority_queue<int, less<int>, thin_heap_tag> c;
 115     some_op_sequence(c);
 116   }
 117
 118   return 0;
 119 }