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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2014 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_erase_if.cpp
  34  * Example showing how to conditionally erase values from a priority queue.
  35  */
  36
  37 /**
  38  * This example shows how to erase from a priority queue using erase_if.
  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   __gnu_pbds::priority_queue<int> p;
  53
  54   // First we insert some values into the container.
  55   for (int i = 0; i < 1000; ++i)
  56     p.push(i);
  57
  58   assert(p.top() == 999);
  59
  60   // Now we erase all values that satisfy some predicate, in this case
  61   // one that returns true for all those larger than 500.
  62   p.erase_if(bind1st(less<int>(), 500));
  63
  64   // The largest value should be now 500.
  65   assert(p.top() == 500);
  66 }
  67