Finish knapsack implementation

Algorithm/Knapsack/Backpack.php

@@ -4,7 +4,7 @@
  *
  * PHP Version 7.4
  *
- * @package   phpOMS\Algorithm\Knappsack
+ * @package   phpOMS\Algorithm\Knapsack
  * @copyright Dennis Eichhorn
  * @license   OMS License 1.0
  * @version   1.0.0
@@ -13,12 +13,12 @@
 
 declare(strict_types=1);
 
-namespace phpOMS\Algorithm\Knappsack;
+namespace phpOMS\Algorithm\Knapsack;
 
 /**
- * Backpack for the Knappsack problem
+ * Backpack for the Knapsack problem
  *
- * @package phpOMS\Algorithm\Knappsack
+ * @package phpOMS\Algorithm\Knapsack
  * @license OMS License 1.0
  * @link    https://orange-management.org
  * @since   1.0.0
@@ -93,6 +93,18 @@ class Backpack
         return $this->cost;
     }
 
+    /**
+     * Get the max allowed costs for the items
+     *
+     * @return float
+     *
+     * @since 1.0.0
+     */
+    public function getMaxCost() : float
+    {
+        return $this->maxCost;
+    }
+
     /**
      * Get items
      *
@@ -108,16 +120,17 @@ class Backpack
     /**
      * Add item to backpack
      *
-     * @param Item $item Item
+     * @param Item  $item     Item
+     * @param mixed $quantity Quantity of the item
      *
      * @return void
      *
      * @since 1.0.0
      */
-    public function addItem(Item $item) : void
+    public function addItem(Item $item, $quantity = 1) : void
     {
-        $this->items[] = $item;
+        $this->items[] = ['item' => $item, 'quantity' => $quantity];
-        $this->value  += $item->getValue();
+        $this->value  += $item->getValue() * $quantity;
-        $this->cost   += $item->getCost();
+        $this->cost   += $item->getCost() * $quantity;
     }
 }

Algorithm/Knapsack/Bounded.php

@@ -0,0 +1,87 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   phpOMS\Algorithm\Knapsack
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+
+declare(strict_types=1);
+
+namespace phpOMS\Algorithm\Knapsack;
+
+/**
+ * Bounded knapsack algorithm
+ *
+ * This algorithm only works for integer cost, values and quantities!
+ *
+ * @package phpOMS\Algorithm\Knapsack
+ * @license OMS License 1.0
+ * @link    https://orange-management.org
+ * @since   1.0.0
+ */
+final class Bounded
+{
+    /**
+     * Fill the backpack with items
+     *
+     * This algorithm only works for integer cost, values and quantities!
+     *
+     * @param array    $items    Items to fill the backpack with ['item' => Item, 'quantity' => ?]
+     * @param Backpack $backpack Backpack to fill
+     *
+     * @return Backpack
+     *
+     * @since 1.0.0
+     */
+    public static function solve(array $items, Backpack $backpack) : Backpack
+    {
+        $n       = \count($items);
+        $maxCost = (int) $backpack->getMaxCost();
+        $mm      = \array_fill(0, ($maxCost + 1), 0);
+        $m       = [];
+        $m[0]    = $mm;
+
+        for ($i = 1; $i <= $n; ++$i) {
+            $m[$i] = $mm;
+
+            for ($j = 0; $j <= $maxCost; ++$j) {
+                $m[$i][$j] = $m[$i - 1][$j];
+
+                for ($k = 1; $k <= $items[$i - 1]['quantity']; $k++) {
+                    if ($k * ((int) $items[$i - 1]['item']->getCost()) > $j) {
+                        break;
+                    }
+
+                    $v = $m[$i - 1][$j - $k * ((int) $items[$i - 1]['item']->getCost())] + $k * ((int) $items[$i - 1]['item']->getValue());
+
+                    if ($v > $m[$i][$j]) {
+                        $m[$i][$j] = $v;
+                    }
+                }
+            }
+        }
+
+        $s = 0;
+        for ($i = $n, $j = $maxCost; $i > 0; --$i) {
+            $s = 0;
+            $v = $m[$i][$j];
+
+            for ($k = 0; $v !== $m[$i - 1][$j] + $k * ((int) $items[$i - 1]['item']->getValue()); ++$k) {
+                $s++;
+                $j -= (int) $items[$i - 1]['item']->getCost();
+            }
+
+            if ($s > 0) {
+                $backpack->addItem($items[$i - 1]['item'], $s);
+            }
+        }
+
+        return $backpack;
+    }
+}

Algorithm/Knapsack/Continuous.php

@@ -0,0 +1,61 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   phpOMS\Algorithm\Knapsack
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+
+declare(strict_types=1);
+
+namespace phpOMS\Algorithm\Knapsack;
+
+/**
+ * Continuous knapsack algorithm
+ *
+ * @package phpOMS\Algorithm\Knapsack
+ * @license OMS License 1.0
+ * @link    https://orange-management.org
+ * @since   1.0.0
+ */
+final class Continuous
+{
+    /**
+     * Fill the backpack with items
+     *
+     * @param array    $items    Items to fill the backpack with ['item' => Item, 'quantity' => ?]
+     * @param Backpack $backpack Backpack to fill
+     *
+     * @return Backpack
+     *
+     * @since 1.0.0
+     */
+    public static function solve(array $items, Backpack $backpack) : Backpack
+    {
+        usort($items, function($a, $b) {
+            return $a['item']->getValue() / $a['item']->getCost() < $b['item']->getValue() / $b['item']->getCost();
+        });
+
+        $availableSpace = $backpack->getMaxCost();
+
+        foreach ($items as $item) {
+            if ($availableSpace <= 0.0) {
+                break;
+            }
+
+            $backpack->addItem(
+                $item['item'],
+                $quantity = \min($item['quantity'], $availableSpace / $item['item']->getCost())
+            );
+
+            $availableSpace -= $quantity * $item['item']->getCost();
+        }
+
+        return $backpack;
+    }
+}

Algorithm/Knapsack/Item.php

@@ -4,7 +4,7 @@
  *
  * PHP Version 7.4
  *
- * @package   phpOMS\Algorithm\Knappsack
+ * @package   phpOMS\Algorithm\Knapsack
  * @copyright Dennis Eichhorn
  * @license   OMS License 1.0
  * @version   1.0.0
@@ -12,12 +12,12 @@
  */
 declare(strict_types=1);
 
-namespace phpOMS\Algorithm\Knappsack;
+namespace phpOMS\Algorithm\Knapsack;
 
 /**
- * Item in the knappsack
+ * Item in the Knapsack
  *
- * @package phpOMS\Algorithm\Knappsack
+ * @package phpOMS\Algorithm\Knapsack
  * @license OMS License 1.0
  * @link    https://orange-management.org
  * @since   1.0.0
@@ -30,7 +30,7 @@ class Item
      * @var   float
      * @since 1.0.0
      */
-    private $value = 0.0;
+    private float $value = 0.0;
 
     /**
      * Cost of the item
@@ -38,7 +38,15 @@ class Item
      * @var   float
      * @since 1.0.0
      */
-    private $cost = 0.0;
+    private float $cost = 0.0;
+
+    /**
+     * Name of the item
+     *
+     * @var   string
+     * @since 1.0.0
+     */
+    private string $name = '';
 
     /**
      * Cosntructor.
@@ -48,10 +56,11 @@ class Item
      *
      * @since 1.0.0
      */
-    public function __construct(float $value, float $cost)
+    public function __construct(float $value, float $cost, string $name = '')
     {
         $this->value = $value;
         $this->cost  = $cost;
+        $this->name  = $name;
     }
 
     /**
@@ -77,4 +86,16 @@ class Item
     {
         return $this->cost;
     }
+
+    /**
+     * Get the name of the item
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    public function getName() : string
+    {
+        return $this->name;
+    }
 }