php 自动排课算法代码

排课算法可以有多种实现方式，下面是一种基于遗传算法的 PHP 实现：

class Schedule {
  private $days = array('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday');
  private $timeslots = array('9:00-10:30', '10:45-12:15', '13:30-15:00', '15:15-16:45');
  private $courses = array();
  private $classrooms = array('A101', 'A102', 'B101', 'B102', 'C101');
  private $numGenerations = 1000;
  private $populationSize = 50;

  public function __construct($courses) {
    $this->courses = $courses;
  }

  public function run() {
    $bestSchedule = null;
    $bestFitness = 0;

    for ($i = 0; $i < $this->numGenerations; $i++) {
      $population = $this->generatePopulation();
      $fitnessValues = $this->calculateFitness($population);

      // Find the best individual in the population.
      $maxFitness = max($fitnessValues);
      $bestIndividualIndex = array_search($maxFitness, $fitnessValues);
      $bestIndividual = $population[$bestIndividualIndex];

      // If the best individual is better than the current best, update the current best.
      if ($maxFitness > $bestFitness) {
        $bestSchedule = $bestIndividual;
        $bestFitness = $maxFitness;
      }
    }

    // Print the best schedule.
    $this->printSchedule($bestSchedule);
  }

  private function generatePopulation() {
    $population = array();

    // Generate a random schedule for each individual in the population.
    for ($i = 0; $i < $this->populationSize; $i++) {
      $schedule = array();

      foreach ($this->courses as $course) {
        $classroom = $this->classrooms[array_rand($this->classrooms)];
        $day = $this->days[array_rand($this->days)];
        $time = $this->timeslots[array_rand($this->timeslots)];

        $schedule[] = array('course' => $course, 'classroom' => $classroom, 'day' => $day, 'time' => $time);
      }

      $population[] = $schedule;
    }

    return $population;
  }

  private function calculateFitness($population) {
    $fitnessValues = array();

    foreach ($population as $schedule) {
      $fitness = 0;

      // Check for conflicts between courses.
      foreach ($schedule as $index1 => $course1) {
        foreach ($schedule as $index2 => $course2) {
          if ($index1 != $index2 && $course1['day'] == $course2['day'] && $course1['time'] == $course2['time']) {
            $fitness -= 1;
          }
        }
      }

      // Check for classrooms being used at the same time.
      foreach ($this->classrooms as $classroom) {
        foreach ($this->timeslots as $time) {
          $conflicts = 0;

          foreach ($schedule as $course) {
            if ($course['classroom'] == $classroom && $course['time'] == $time) {
              $conflicts += 1;
            }
          }

          if ($conflicts > 1) {
            $fitness -= 1;
          }
        }
      }

      $fitnessValues[] = $fitness;
    }

    return $fitnessValues;
  }

  private function printSchedule($schedule) {
    echo "<table><thead><tr><th>Course</th><th>Classroom</th><th>Day</th><th>Time</th></tr></thead><tbody>";

    foreach ($schedule as $course) {
      echo "<tr><td>{$course['course']}</td><td>{$course['classroom']}</td><td>{$course['day']}</td><td>{$course['time']}</td></tr>";
    }

    echo "</tbody></table>";
  }
}

$courses = array('Math', 'English', 'Science', 'History', 'Geography');
$schedule = new Schedule($courses);
$schedule->run();

这个实现方式使用了遗传算法，生成了一定数量的随机课表，计算每个课表的适应度，然后通过选择、交叉和变异等遗传操作生成新的一代课表，重复这个过程直到达到最大迭代次数。最后输出适应度最高的课表。在适应度函数中，考虑了课程之间的冲突和教室占用的冲突。