死锁¶

def banker_algorithm(processes, resources, available, max_need, allocation):
    """
    银行家算法的安全性检查
    """
    n = len(processes)  # 进程数
    m = len(resources)  # 资源种类数

    # 计算 Need 矩阵
    need = [[max_need[i][j] - allocation[i][j] 
             for j in range(m)] for i in range(n)]

    # 初始化
    work = available.copy()
    finish = [False] * n
    safe_sequence = []

    # 寻找安全序列
    while len(safe_sequence) < n:
        found = False
        for i in range(n):
            if not finish[i]:
                # 检查 Need[i] <= Work
                if all(need[i][j] <= work[j] for j in range(m)):
                    # 进程可以执行
                    work = [work[j] + allocation[i][j] for j in range(m)]
                    finish[i] = True
                    safe_sequence.append(processes[i])
                    found = True
                    break

        if not found:
            # 无法找到可执行进程，系统不安全
            return False, []

    return True, safe_sequence

# 资源请求处理
def request_resources(process_id, request, available, need, allocation):
    """
    处理进程的资源请求
    """
    m = len(request)

    # 1. 检查请求合法性
    if any(request[j] > need[process_id][j] for j in range(m)):
        return False, "Request exceeds need"

    # 2. 检查资源可用性
    if any(request[j] > available[j] for j in range(m)):
        return False, "Insufficient resources, need to wait"

    # 3. 尝试分配（模拟）
    temp_available = [available[j] - request[j] for j in range(m)]
    temp_allocation = [allocation[process_id][j] + request[j] 
                       for j in range(m)]
    temp_need = [need[process_id][j] - request[j] for j in range(m)]

    # 4. 安全性检查（需要调用上面的 banker_algorithm）
    # 如果安全，则正式分配；否则撤销

    return True, "Allocation successful"