libstdc++-v3/testsuite/25_algorithms/pop_heap/complexity.cc

   1 // Copyright (C) 2014-2020 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do run { target c++11 } }
  19 // { dg-require-normal-mode "" }
  20 // { dg-require-cmath "" }
  21 // { dg-require-cstdint "" }
  22 // { dg-require-effective-target random_device }
  23
  24 #include <cmath>
  25 #include <random>
  26 #include <vector>
  27 #include <algorithm>
  28
  29 #include <testsuite_counter_type.h>
  30 #include <testsuite_hooks.h>
  31
  32 void test01()
  33 {
  34   using __gnu_test::counter_type;
  35   const std::size_t nb_values = 1000;
  36
  37   std::random_device dev;
  38   std::uniform_int_distribution<int> dist;
  39   std::vector<counter_type> values;
  40   values.reserve(nb_values);
  41   for (std::size_t i = 0; i != nb_values; ++i)
  42     values.push_back(dist(dev));
  43
  44   std::make_heap(values.begin(), values.end());
  45
  46   counter_type::reset();
  47
  48   std::pop_heap(values.begin(), values.end());
  49
  50   VERIFY( counter_type::less_compare_count <= 2.0 * std::log2(nb_values) );
  51 }
  52
  53 int main()
  54 {
  55   test01();
  56   return 0;
  57 }