1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
// Copyright (c) 2012
// Inria Nancy - Grand Est
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1.1/Generator/include/CGAL/Combination_enumerator.h $
// $Id: include/CGAL/Combination_enumerator.h 08b27d3db14 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Samuel Hornus
#ifndef CGAL_COMBINATION_ENUMERATOR_H
#define CGAL_COMBINATION_ENUMERATOR_H
#include <CGAL/disable_warnings.h>
#include <CGAL/basic.h>
#include <vector>
namespace CGAL {
template< typename T >
class Combination_enumerator
{
// types and member data
typedef std::vector<T> Combination;
Combination combi_;
const int k_;
const T first_;
const T beyond_;
const T max_at_pos_0_;
// protected methods
const T & element(const int i) const
{
CGAL_assertion( 0 <= i && i < k_ );
return combi_[i];
}
T & element(const int i)
{
CGAL_assertion( 0 <= i && i < k_ );
return combi_[i];
}
public:
// For generating all the combinations of |k| distinct elements in the
// interval [first, beyond] (both included)
Combination_enumerator(const int k, const T & first, const T & beyond)
: combi_(k), k_(k), first_(first), beyond_(beyond), max_at_pos_0_(beyond - k)
{
CGAL_assertion_msg( (1 <= k) && (k <= static_cast<int>(beyond - first)), "wrong value of k");
reset();
}
Combination_enumerator(const Combination_enumerator & c)
: combi_(c.combi_), k_(c.k_), first_(c.first_), beyond_(c.beyond_), max_at_pos_0_(c.max_at_pos_0_)
{}
int number_of_elements() const
{
return k_;
}
const T & min_element() const
{
return first_;
}
const T & beyond_element() const
{
return beyond_;
}
void reset()
{
T elem(min_element());
for( int i = 0; i < number_of_elements(); ++i )
{
element(i) = elem;
++elem;
}
}
bool finished() const
{
return max_at_pos_0_ < element(0);
}
const T & operator[](const int i) const
{
return element(i);
}
void operator++()
{
int i(k_ - 1);
T max_at_pos_i(beyond_-1);
while( ( i >= 0 ) && ( ! (element(i) < max_at_pos_i) ) )
{
--i;
--max_at_pos_i;
}
if( -1 == i )
{
if( element(0) == max_at_pos_0_ )
++element(0); // mark then end of the enumeration with an impossible value.
// Note than when we have arrived at the end of the enumeration, applying
// operator++() again does not change anything, so it is safe to
// apply it too many times.
}
else
{
++element(i);
for( int j = i + 1; j < k_; ++j )
element(j) = element(i) + (j - i);
}
}
Combination_enumerator operator++(int)
{
Combination_enumerator tmp(*this);
++(*this);
return tmp;
}
};
} // end of namespace CGAL
#include <CGAL/enable_warnings.h>
#endif // CGAL_COMBINATION_ENUMERATOR_H
|
