|
1
|
|
|
<?php |
|
2
|
|
|
/** |
|
3
|
|
|
* Box packing (3D bin packing, knapsack problem). |
|
4
|
|
|
* |
|
5
|
|
|
* @author Doug Wright |
|
6
|
|
|
*/ |
|
7
|
|
|
|
|
8
|
|
|
namespace DVDoug\BoxPacker; |
|
9
|
|
|
|
|
10
|
|
|
/** |
|
11
|
|
|
* List of items to be packed, ordered by volume. |
|
12
|
|
|
* |
|
13
|
|
|
* @author Doug Wright |
|
14
|
|
|
*/ |
|
15
|
|
|
class ItemList extends \SplMaxHeap |
|
16
|
|
|
{ |
|
17
|
|
|
/** |
|
18
|
|
|
* Compare elements in order to place them correctly in the heap while sifting up. |
|
19
|
|
|
* |
|
20
|
|
|
* @see \SplMaxHeap::compare() |
|
21
|
|
|
* |
|
22
|
|
|
* @param mixed $itemA |
|
23
|
|
|
* @param mixed $itemB |
|
24
|
|
|
* |
|
25
|
|
|
* @return int |
|
26
|
|
|
*/ |
|
27
|
37 |
|
public function compare($itemA, $itemB) |
|
28
|
|
|
{ |
|
29
|
37 |
|
if ($itemA->getVolume() > $itemB->getVolume()) { |
|
30
|
20 |
|
return 1; |
|
31
|
36 |
|
} elseif ($itemA->getVolume() < $itemB->getVolume()) { |
|
32
|
17 |
|
return -1; |
|
33
|
32 |
|
} elseif ($itemA->getWeight() !== $itemB->getWeight()) { |
|
34
|
3 |
|
return $itemA->getWeight() - $itemB->getWeight(); |
|
35
|
32 |
|
} elseif ($itemA->getDescription() < $itemB->getDescription()) { |
|
36
|
8 |
|
return 1; |
|
37
|
|
|
} else { |
|
38
|
30 |
|
return -1; |
|
39
|
|
|
} |
|
40
|
|
|
} |
|
41
|
|
|
|
|
42
|
|
|
/** |
|
43
|
|
|
* Do a bulk create. |
|
44
|
|
|
* |
|
45
|
|
|
* @param Item[] $items |
|
46
|
|
|
* @return ItemList |
|
47
|
|
|
*/ |
|
48
|
|
|
public static function fromArray(array $items) |
|
49
|
|
|
{ |
|
50
|
|
|
$list = new static(); |
|
51
|
|
|
foreach ($items as $item) { |
|
52
|
|
|
$list->insert($item); |
|
53
|
|
|
} |
|
54
|
|
|
return $list; |
|
55
|
|
|
} |
|
56
|
|
|
|
|
57
|
|
|
/** |
|
58
|
|
|
* Get copy of this list as a standard PHP array. |
|
59
|
|
|
* |
|
60
|
|
|
* @return Item[] |
|
61
|
|
|
*/ |
|
62
|
17 |
|
public function asArray() |
|
63
|
|
|
{ |
|
64
|
17 |
|
$return = []; |
|
65
|
17 |
|
foreach (clone $this as $item) { |
|
66
|
17 |
|
$return[] = $item; |
|
67
|
|
|
} |
|
68
|
|
|
|
|
69
|
17 |
|
return $return; |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
|
|
/** |
|
73
|
|
|
* @internal |
|
74
|
|
|
* |
|
75
|
|
|
* @param int $n |
|
76
|
|
|
* @return ItemList |
|
77
|
|
|
*/ |
|
78
|
3 |
|
public function topN($n) |
|
79
|
|
|
{ |
|
80
|
3 |
|
$workingList = clone $this; |
|
81
|
3 |
|
$topNList = new self(); |
|
82
|
3 |
|
$i = 0; |
|
83
|
3 |
|
while(!$workingList->isEmpty() && $i < $n) { |
|
84
|
3 |
|
$topNList->insert($workingList->extract()); |
|
85
|
3 |
|
$i++; |
|
86
|
|
|
} |
|
87
|
|
|
|
|
88
|
3 |
|
return $topNList; |
|
89
|
|
|
} |
|
90
|
|
|
|
|
91
|
|
|
/** |
|
92
|
|
|
* Remove item from list. |
|
93
|
|
|
* |
|
94
|
|
|
* @param Item $item |
|
95
|
|
|
*/ |
|
96
|
|
|
public function remove(Item $item) |
|
97
|
|
|
{ |
|
98
|
|
|
$workingSet = []; |
|
99
|
|
|
while (!$this->isEmpty()) { |
|
100
|
|
|
$workingSet[] = $this->extract(); |
|
101
|
|
|
} |
|
102
|
|
|
|
|
103
|
|
|
$removed = false; // there can be multiple identical items, ensure that only 1 is removed |
|
104
|
|
|
foreach ($workingSet as $workingSetItem) { |
|
105
|
|
|
if (!$removed && $workingSetItem === $item) { |
|
106
|
|
|
$removed = true; |
|
107
|
|
|
} else { |
|
108
|
|
|
$this->insert($workingSetItem); |
|
109
|
|
|
} |
|
110
|
|
|
} |
|
111
|
|
|
|
|
112
|
|
|
} |
|
113
|
|
|
} |
|
114
|
|
|
|
dvdoug /
BoxPacker
