在双向链表中间插入新节点的Python程序

当需要在双向链表的中间插入新节点时，需要创建一个名为“Node”的类。在此类中，有三个属性：数据（即节点中的数据），链表中下一个节点的访问权限，以及链表中上一个节点的访问权限。

下面是示例 −

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例子

class Node:
   def __init__(self, my_data):
      self.previous = None
      self.data = my_data
      self.next = None
class double_list:
   def __init__(self):
      self.head = None
      self.tail = None
      self.size = 0
   def add_data(self, my_data):
      new_node = Node(my_data)
      if(self.head == None):
         self.head = self.tail = new_node
         self.head.previous = None
         self.tail.next = None
      else:
         self.tail.next = new_node
         new_node.previous = self.tail
         self.tail = new_node
         self.tail.next = None
      self.size = self.size + 1
   def print_it(self):
      curr = self.head
      if (self.head == None):
         print("The list is empty")
         return
      print("The nodes in the doubly linked list are :")
      while curr != None:
         print(curr.data)
         curr = curr.next
   def add_data_in_middle(self, my_data):
      new_node = Node(my_data);
      if(self.head == None):
         self.head = self.tail = new_node;
         self.head.previous = None;
         self.tail.next = None;
      else:
         curr = self.head;
         mid = (self.size//2) if(self.size % 2 == 0) else ((self.size+1)//2);
         for i in range(1, mid):
            curr = curr.next;
         temp = curr.next;
         temp.previous = curr;
         curr.next = new_node;
         new_node.previous = curr;
         new_node.next = temp;
         temp.previous = new_node;
      self.size = self.size + 1;
my_instance = double_list()
print("Elements are being added to the doubly linked list")
my_instance.add_data(10)
my_instance.add_data(24)
my_instance.add_data(54)
print("在列表中间添加元素")
my_instance.add_data_in_middle(77)
my_instance.print_it()
my_instance.add_data_in_middle(92)
my_instance.print_it()

输出

Elements are being added to the doubly linked list
在列表中间添加元素
The nodes in the doubly linked list are :
10
24
77
54
The nodes in the doubly linked list are :
10
24
92
77
54