时间片轮转调度算法与银行家算法结 合，设计一种时间片轮转调度算法从进程就绪队列 中选择一个进程，该进程发出资源请求并启动银行 家算法。 代码演示

以下是一个基于时间片轮转调度算法与银行家算法结合的简单示例代码：

class Process:
    def __init__(self, pid, arrival_time, burst_time, allocated_resources):
        self.pid = pid
        self.arrival_time = arrival_time
        self.burst_time = burst_time
        self.resources_needed = allocated_resources
        self.remaining_time = burst_time
        self.waiting_time = 0
        self.turnaround_time = 0
        self.completed = False

class Scheduler:
    def __init__(self, processes, time_slice, resources):
        self.processes = processes
        self.time_slice = time_slice
        self.resources = resources
        self.ready_queue = []
        self.blocked_queue = []
        self.completed_queue = []

    def start(self):
        current_time = 0

        while True:
            # 将到达时间已经到达的进程加入就绪队列
            for process in self.processes:
                if process.arrival_time == current_time:
                    self.ready_queue.append(process)

            # 如果就绪队列为空，则等待下一个进程到达
            if not self.ready_queue:
                current_time += 1
                continue

            # 选择一个进程执行，使用时间片轮转调度算法
            current_process = self.ready_queue.pop(0)
            for i in range(self.time_slice):
                # 如果进程运行结束，则将其加入完成队列，并释放已分配的资源
                if current_process.remaining_time == 0:
                    current_process.completed = True
                    current_process.turnaround_time = current_time - current_process.arrival_time
                    self.completed_queue.append(current_process)
                    for j in range(len(self.resources)):
                        self.resources[j] += current_process.resources_needed[j]
                    break

                # 如果进程发出资源请求，则启动银行家算法来判断是否能够满足其资源需求
                if current_process.remaining_time % 2 == 0:
                    if self.bankers_algorithm(current_process):
                        self.blocked_queue.remove(current_process)
                        self.ready_queue.append(current_process)
                    else:
                        # 如果无法满足其资源需求，则将其加入阻塞队列
                        self.blocked_queue.append(current_process)
                        break

                current_process.remaining_time -= 1
                current_time += 1

            # 如果进程未运行结束，则将其加入就绪队列尾部
            if not current_process.completed:
                current_process.waiting_time += self.time_slice
                self.ready_queue.append(current_process)

            # 将阻塞队列中的进程再次加入就绪队列
            for blocked_process in self.blocked_queue:
                if self.bankers_algorithm(blocked_process):
                    self.blocked_queue.remove(blocked_process)
                    self.ready_queue.append(blocked_process)

            # 如果所有进程都已完成，则退出循环
            if all(process.completed for process in self.processes):
                break

        # 打印统计信息
        self.print_stats()

    def bankers_algorithm(self, process):
        """银行家算法"""
        for i in range(len(self.resources)):
            # 如果该进程所需的资源数量超过了系统中的可用资源数量，则拒绝其请求
            if process.resources_needed[i] > self.resources[i]:
                return False

        # 如果分配给该进程所需的资源后，系统中剩余的资源无法满足其他进程的需求，则拒绝该进程的请求
        for i in range(len(self.resources)):
            available_resources = self.resources[i] - process.resources_needed[i]
            for j in range(len(self.processes)):
                if not self.processes[j].completed and self.processes[j] != process:
                    if self.processes[j].resources_needed[i] > available_resources:
                        return False

        # 否则，分配资源给该进程，并更新系统中剩余的资源数量
        for i in range(len(self.resources)):
            self.resources[i] -= process.resources_needed[i]

        return True

    def print_stats(self):
        """打印统计信息"""
        total_waiting_time = 0
        total_turnaround_time = 0
        print("Process ID\tWaiting Time\tTurnaround Time")
        for process in self.completed_queue:
            total_waiting_time += process.waiting_time
            total_turnaround_time += process.turnaround_time
            print(f"{process.pid}\t\t{process.waiting_time}\t\t{process.turnaround_time}")
        print(f"Average waiting time: {total_waiting_time / len(self.completed_queue)}")
        print(f"Average turnaround time: {total_turnaround_time / len(self.completed_queue)}")

# 测试
processes = [
    Process(1, 0, 10, [2, 3, 0]),
    Process(2, 1, 5, [1, 1, 2]),
    Process(3, 2, 3, [3, 1, 2]),
    Process(4, 3, 8, [0, 2, 1])
]

resources = [3, 3, 3]
scheduler = Scheduler(processes, 2, resources)
scheduler.start()

在这个示例代码中，我们定义了一个 `Process` 类来表示进程，其中包括进程的 ID、到达时间、执行时间、已分配的资源数量、剩余执行时间、等待时间和周转时间等信息。我们还定义了一个 `Scheduler` 类来表示调度器，其中包括就绪队列、阻塞队列、完成队列和可用资源数量等信息。在 `Scheduler` 类中，我们实现了时间片轮转调度算法和银行家算法，并通过调用 `start` 方法来启动调度器，按照时间片轮转调度算法来调度进程并处理资源请求。最后，我们打印了一些统计信息来评估调度器的性能。