libstdc++-v3/testsuite/25_algorithms/next_permutation/constrained.cc

   1 // Copyright (C) 2020-2023 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-options "-std=gnu++2a" }
  19 // { dg-do run { target c++2a } }
  20
  21 #include <algorithm>
  22 #include <testsuite_hooks.h>
  23 #include <testsuite_iterators.h>
  24
  25 using __gnu_test::test_container;
  26 using __gnu_test::test_range;
  27 using __gnu_test::bidirectional_iterator_wrapper;
  28
  29 namespace ranges = std::ranges;
  30
  31 void
  32 test01()
  33 {
  34   int x[] = {1, 2, 3, 4, 5};
  35   int y[] = {1, 2, 3, 4, 5};
  36
  37   for (int i = 0; i <= 5; i++)
  38     {
  39       test_container<int, bidirectional_iterator_wrapper> cx(x, x+i);
  40       test_container<int, bidirectional_iterator_wrapper> cy(y, y+i);
  41       for (int j = 0; ; j++)
  42         {
  43           auto found1 = std::next_permutation(cx.begin(), cx.end());
  44           auto [last,found2] = ranges::next_permutation(cy.begin(), cy.end());
  45           VERIFY( found1 == found2 );
  46           VERIFY( ranges::equal(cx, cy) );
  47           if (!found2)
  48             break;
  49         }
  50     }
  51 }
  52
  53 void
  54 test02()
  55 {
  56   int x[] = {5, 4, 3, 2, 1};
  57   test_range<int, bidirectional_iterator_wrapper> rx(x);
  58   auto [last,found] = ranges::next_permutation(rx, ranges::greater{});
  59   VERIFY( found && last == rx.end() );
  60   VERIFY( last == rx.end() );
  61   VERIFY( ranges::equal(rx, (int[]){5,4,3,1,2}) );
  62   ranges::next_permutation(rx, {}, [] (int a) { return -a; });
  63   VERIFY( ranges::equal(rx, (int[]){5,4,2,3,1}) );
  64
  65   VERIFY( !ranges::next_permutation(x, x).found );
  66   VERIFY( !ranges::next_permutation(x, x+1).found );
  67 }
  68
  69 constexpr bool
  70 test03()
  71 {
  72   int x[] = {1,2,3};
  73   ranges::next_permutation(x);
  74   return ranges::equal(x, (int[]){1,3,2});
  75 }
  76
  77 int
  78 main()
  79 {
  80   test01();
  81   test02();
  82   static_assert(test03());
  83 }