python多级反馈队列调度算法代码

Python多级反馈队列调度算法代码如下：

class Process:
    def __init__(self, name, arrival_time, burst_time):
        self.name = name
        self.arrival_time = arrival_time
        self.burst_time = burst_time
        self.waiting_time = 0
        self.remaining_time = burst_time
    
    def execute(self, time_quantum):
        if self.remaining_time > time_quantum:
            self.remaining_time -= time_quantum
        else:
            self.waiting_time = self.waiting_time + self.remaining_time  # 更新等待时间
            self.remaining_time = 0

    def is_finished(self):
        return self.remaining_time == 0


def multi_feedback_queue(processes, priorities, time_quantum):
    queue = [[] for _ in range(len(priorities))]  # 创建多级队列
    current_time = 0
    waiting_time = 0
    
    while True:
        for i, p in enumerate(processes):
            if p.arrival_time <= current_time:  # 将到达时间小于等于当前时间的进程加入队列
                queue[priorities[i]].append(p)
        
        for q in queue:
            if q:  # 队列不为空
                process = q.pop(0)  # 取出队首进程
                process.execute(time_quantum)  # 执行时间片
                current_time += time_quantum  # 更新当前时间
                
                if process.is_finished():
                    waiting_time += process.waiting_time
                else:
                    q.append(process)  # 未完成的进程放回队列
            else:
                current_time += 1  # 队列为空时，时间流逝
        
        if not any(queue):  # 所有队列都为空时退出循环
            break
    
    average_waiting_time = waiting_time / len(processes)
    return average_waiting_time


# 测试代码
if __name__ == '__main__':
    processes = [
        Process('P1', 0, 10),
        Process('P2', 3, 1),
        Process('P3', 4, 3),
        Process('P4', 8, 2),
    ]
    priorities = [0, 1, 2, 3]  # 进程对应的优先级
    time_quantum = 2
    average_waiting_time = multi_feedback_queue(processes, priorities, time_quantum)
    print(f"平均等待时间: {average_waiting_time}")

以上代码实现了一个多级反馈队列调度算法，根据进程的到达时间和优先级将进程放入对应的队列中，并按照时间片的方式执行进程。当一个进程完成时，更新其等待时间，并根据是否执行完毕重新放入对应的队列中。最终计算出所有进程的平均等待时间。