应用循环首次适应法模拟电脑内存的分配和释放，使用双链表-Simulation cycle for the first time to adapt to memory allocation and release of

双向循环链表，函数初始化，函数功能：增加节点，删除节点，查找节点。-Two-way circular linked list function initializes the function: add nodes, delete nodes, find nodes.