From a504f6bd0e170e1b4586834c28fde71936c3d5c0 Mon Sep 17 00:00:00 2001
From: Dennis Eichhorn <spl1nes.com@googlemail.com>
Date: Thu, 17 Oct 2019 10:49:52 +0200
Subject: [PATCH] Implement weighted job scheduling

---
 Algorithm/JobScheduling/Job.php      | 123 ++++++++++++++++++++++++
 Algorithm/JobScheduling/Weighted.php | 135 +++++++++++++++++++++++++++
 2 files changed, 258 insertions(+)

diff --git a/Algorithm/JobScheduling/Job.php b/Algorithm/JobScheduling/Job.php
index e69de29bb..73fda98de 100644
--- a/Algorithm/JobScheduling/Job.php
+++ b/Algorithm/JobScheduling/Job.php
@@ -0,0 +1,123 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   phpOMS\Algorithm\JobScheduling
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace phpOMS\Algorithm\JobScheduling;
+
+/**
+ * Job for scheduling
+ *
+ * @package phpOMS\Algorithm\JobScheduling
+ * @license OMS License 1.0
+ * @link    https://orange-management.org
+ * @since   1.0.0
+ */
+class Job
+{
+    /**
+     * Value of the job
+     *
+     * @var   float
+     * @since 1.0.0
+     */
+    private float $value = 0.0;
+
+    /**
+     * Start time of the job
+     *
+     * @var   \DateTime
+     * @since 1.0.0
+     */
+    private \DateTime $start;
+
+    /**
+     * End time of the job
+     *
+     * @var   \DateTime
+     * @since 1.0.0
+     */
+    private ?\DateTime $end = null;
+
+    /**
+     * Name of the job
+     *
+     * @var   string
+     * @since 1.0.0
+     */
+    private string $name = '';
+
+    /**
+     * Cosntructor.
+     *
+     * @param float          $value Value of the job
+     * @param \DateTime      $start Start time of the job
+     * @param null|\DateTime $end   End time of the job
+     *
+     * @since 1.0.0
+     */
+    public function __construct(float $value, \DateTime $start, ?\DateTime $end, string $name = '')
+    {
+        $this->value = $value;
+        $this->start = $start;
+        $this->end   = $end;
+        $this->name  = $name;
+    }
+
+    /**
+     * Get value of the job
+     *
+     * @return float
+     *
+     * @since 1.0.0
+     */
+    public function getValue() : float
+    {
+        return $this->value;
+    }
+
+    /**
+     * Get start time of the job
+     *
+     * @return \DateTime
+     *
+     * @since 1.0.0
+     */
+    public function getStart() : \DateTime
+    {
+        return $this->start;
+    }
+
+    /**
+     * Get end time of the job
+     *
+     * @return \DateTime
+     *
+     * @since 1.0.0
+     */
+    public function getEnd() : ?\DateTime
+    {
+        return $this->end;
+    }
+
+    /**
+     * Get the name of the job
+     *
+     * @return string
+     *
+     * @since 1.0.0
+     */
+    public function getName() : string
+    {
+        return $this->name;
+    }
+}
diff --git a/Algorithm/JobScheduling/Weighted.php b/Algorithm/JobScheduling/Weighted.php
index e69de29bb..423363492 100644
--- a/Algorithm/JobScheduling/Weighted.php
+++ b/Algorithm/JobScheduling/Weighted.php
@@ -0,0 +1,135 @@
+<?php
+/**
+ * Orange Management
+ *
+ * PHP Version 7.4
+ *
+ * @package   phpOMS\Algorithm\JobScheduling
+ * @copyright Dennis Eichhorn
+ * @license   OMS License 1.0
+ * @version   1.0.0
+ * @link      https://orange-management.org
+ */
+declare(strict_types=1);
+
+namespace phpOMS\Algorithm\JobScheduling;
+
+/**
+ * Job scheduling algorithm with no overlapping jobs
+ *
+ * @package phpOMS\Algorithm\JobScheduling
+ * @license OMS License 1.0
+ * @link    https://orange-management.org
+ * @since   1.0.0
+ */
+final class Weighted
+{
+    /**
+     * Sort jobs by end date.
+     *
+     * @param Jobs $j1 Job 1
+     * @param Jobs $j2 Job 2
+     *
+     * @return int
+     *
+     * @since 1.0.0
+     */
+    private static function sortByEnd(Job $j1, Job $j2) : int
+    {
+        if ($j1->getEnd() === null && $j2->getEnd() !== null) {
+            return 1;
+        }
+
+        if ($j1->getEnd() === null && $j2->getEnd() === null) {
+            return 0;
+        }
+
+        if ($j1->getEnd() !== null && $j2->getEnd() === null) {
+            return -1;
+        }
+
+        return $j1->getEnd()->getTimestamp() <=> $j2->getEnd()->getTimestamp();
+    }
+
+    /**
+     * Search for a none-conflicting job that comes befor a defined job
+     *
+     * @param Job[] $jobs  List of jobs
+     * @param int   $pivot Job to find the previous job to
+     *
+     * @return int
+     *
+     * @since 1.0.0
+     */
+    private static function binarySearch(array $jobs, int $pivot) : int
+    {
+        $lo = 0;
+        $hi = $pivot - 1;
+
+        while ($lo <= $hi) {
+            $mid = (int) (($lo + $hi) / 2);
+
+            if ($jobs[$mid]->getEnd() !== null
+                && $jobs[$mid]->getEnd()->getTimestamp() <= $jobs[$pivot]->getStart()->getTimestamp()
+            ) {
+                if ($jobs[$mid + 1]->getEnd() !== null
+                    && $jobs[$mid + 1]->getEnd()->getTimestamp() <= $jobs[$pivot]->getStart()->getTimestamp()
+                ) {
+                    $lo = $mid + 1;
+                } else {
+                    return $mid;
+                }
+            } else {
+                $hi = $mid - 1;
+            }
+        }
+
+        return -1;
+    }
+
+    /**
+     * Maximize the value of the job execution without overlapping jobs
+     *
+     * @param Job[] $jobs Jobs to filter
+     *
+     * @return Job[]
+     *
+     * @since 1.0.0
+     */
+    public static function solve(array $jobs) : array
+    {
+        $n = \count($jobs);
+
+        if ($n < 2) {
+            return $jobs;
+        }
+
+        \usort($jobs, [self::class, 'sortByEnd']);
+
+        $valueTable = [$jobs[0]->getValue()];
+
+        $resultTable    = [];
+        $resultTable[0] = [$jobs[0]];
+
+        for ($i = 1; $i < $n; ++$i) {
+            $value = $jobs[$i]->getValue();
+            $jList = [$jobs[$i]];
+            $l     = self::binarySearch($jobs, $i);
+
+            if ($l != -1) {
+                $value += $valueTable[$l];
+                $jList  = \array_merge($resultTable[$l], $jList);
+            }
+
+            if ($value > $valueTable[$i - 1]) {
+                $valueTable[$i]  = $value;
+                $resultTable[$i] = $jList;
+            } else {
+                $valueTable[$i]  = $valueTable[$i - 1];
+                $resultTable[$i] = $resultTable[$i - 1];
+            }
+        }
+
+        return $resultTable[$n - 1];
+    }
+}