1// Copyright (C) 2006-2015 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// 25.3.2 [lib.alg.nth.element]
19
20// { dg-options "-DMAX_SIZE=256" { target simulator } }
21
22#ifndef MAX_SIZE
23#define MAX_SIZE (1 << 10)
24#endif
25
26#include <vector>
27#include <algorithm>
28#include <testsuite_hooks.h>
29
30void
31test_set(std::vector<unsigned>& v, unsigned size)
32{
33  v.clear();
34
35  for (unsigned i = 0; i < size; i += 4)
36    {
37      v.push_back(i / 2);
38      v.push_back((size - 2) - (i / 2));
39    }
40  for (unsigned i = 1; i < size; i += 2)
41    v.push_back(i);
42}
43
44void
45do_test01(unsigned size)
46{
47  bool test __attribute__((unused)) = true;
48
49  std::vector<unsigned> v, s;
50
51  for (unsigned j = 0; j < size; ++j)
52    {
53      test_set(v, size);
54      s = v;
55      std::sort(s.begin(), s.end());
56
57      std::nth_element(v.begin(), v.begin() + j, v.end());
58
59      VERIFY( v[j] == s[j] );
60
61      for (unsigned i = 0; i < j; ++i)
62	VERIFY( !(v[j] < v[i]) );
63
64      for (unsigned i = j; i < v.size(); ++i)
65	VERIFY( !(v[i] < v[j]) );
66    }
67}
68
69void
70test01()
71{
72  for (unsigned size = 4; size <= MAX_SIZE; size <<= 1)
73    do_test01(size);
74}
75
76int main()
77{
78  test01();
79  return 0;
80}
81