libstdc++-v3/testsuite/25_algorithms/heap/1.cc

   1 // Copyright (C) 2001-2025 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 // 25.3.6 Heap operations [lib.alg.heap.operations]
  19
  20 #include <algorithm>
  21 #include <testsuite_hooks.h>
  22
  23 const int A[] = {1, 11, 12, 3, 10, 6, 17, 4, 8, 2, 5, 13, 9, 15, 14, 16, 7};
  24 const int B[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17};
  25 const int C[] = {17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1};
  26 const int N = sizeof(A) / sizeof(int);
  27
  28 // This functor has the equivalent functionality of std::greater<>,
  29 // but there is no dependency on <functional> and it also tracks the
  30 // number of invocations since creation.
  31 class Gt
  32 {
  33 public:
  34   static int count() { return _M_count; }
  35   static void reset() { _M_count = 0; }
  36
  37   bool
  38   operator()(const int& x, const int& y)
  39   {
  40     ++_M_count;
  41     return x > y;
  42   }
  43
  44 private:
  45   static int _M_count;
  46 };
  47
  48 int Gt::_M_count = 0;
  49
  50 // Exercise all of the heap functions for operator<.  The intermediate
  51 // results between push_heap and pop_heap and make_heap and sort_heap
  52 // are not checked (they could be).
  53 void
  54 test01()
  55 {
  56   // sort array s1 using push_heap/pop_heap
  57   int s1[N];
  58   std::copy(A, A + N, s1);
  59   VERIFY(std::equal(s1, s1 + N, A));
  60
  61   for (int i = 2; i <= N; ++i)
  62     std::push_heap(s1, s1 + i);
  63
  64   for (int i = N; i >= 2; --i)
  65     std::pop_heap(s1, s1 + i);
  66
  67   VERIFY(std::equal(s1, s1 + N, B));
  68
  69   // sort array s2 using make_heap/sort_heap
  70   int s2[N];
  71   std::copy(A, A + N, s2);
  72   VERIFY(std::equal(s2, s2 + N, A));
  73
  74   std::make_heap(s2, s2 + N);
  75   std::sort_heap(s2, s2 + N);
  76   VERIFY(std::equal(s2, s2 + N, B));
  77 }
  78
  79 // Perform same tests as above but with the comparison predicate
  80 // versions, and add complexity constraint checks.
  81 void
  82 test02()
  83 {
  84   Gt gt;
  85
  86 #ifndef _GLIBCXX_DEBUG
  87   //const int logN = static_cast<int>(std::log(static_cast<double>(N)) + 0.5);
  88   const int logN = 3;
  89 #endif
  90
  91   int s1[N];
  92   std::copy(A, A + N, s1);
  93   VERIFY(std::equal(s1, s1 + N, A));
  94
  95   for (int i = 2; i <= N; ++i)
  96     {
  97       std::push_heap(s1, s1 + i, gt);
  98 #ifndef _GLIBCXX_DEBUG
  99       VERIFY(gt.count() <= logN);
 100 #endif
 101       gt.reset();
 102     }
 103
 104   for (int i = N; i >= 2; --i)
 105     {
 106       std::pop_heap(s1, s1 + i, gt);
 107 #ifndef _GLIBCXX_DEBUG
 108       VERIFY(gt.count() <= 2 * logN);
 109 #endif
 110       gt.reset();
 111     }
 112
 113   VERIFY(std::equal(s1, s1 + N, C));
 114
 115   // sort array s2 using make_heap/sort_heap
 116   int s2[N];
 117   std::copy(A, A + N, s2);
 118   VERIFY(std::equal(s2, s2 + N, A));
 119
 120   std::make_heap(s2, s2 + N, gt);
 121 #ifndef _GLIBCXX_DEBUG
 122   VERIFY(gt.count() <= 3 * N);
 123 #endif
 124   gt.reset();
 125
 126   std::sort_heap(s2, s2 + N, gt);
 127 #ifndef _GLIBCXX_DEBUG
 128   VERIFY(gt.count() <= N * logN);
 129 #endif
 130
 131   VERIFY(std::equal(s2, s2 + N, C));
 132 }
 133
 134 int
 135 main()
 136 {
 137   test01();
 138   test02();
 139   return 0;
 140 }