定义一个线性链表代码

定义一个线性链表通常涉及创建节点类和链表类。这里是一个简单的 Python 示例：

# 首先定义链表节点类 Node
class Node:
    def __init__(self, data=None):
        self.data = data
        self.next = None

# 然后定义链表类 LinkedList
class LinkedList:
    def __init__(self):
        self.head = None

    # 插入节点到链表头部
    def insert_at_start(self, data):
        new_node = Node(data)
        new_node.next = self.head
        self.head = new_node

    # 插入节点到链表尾部
    def append(self, data):
        if not self.head:
            self.head = Node(data)
            return
        current = self.head
        while current.next:
            current = current.next
        current.next = Node(data)

    # 查找特定值并返回该节点
    def find(self, key):
        current = self.head
        while current and current.data != key:
            current = current.next
        return current

    # 删除节点
    def delete(self, key):
        if not self.head:
            return
        if self.head.data == key:
            self.head = self.head.next
            return
        prev = None
        current = self.head
        while current and current.data != key:
            prev = current
            current = current.next
        if current is None:
            return
        prev.next = current.next

# 使用示例
my_list = LinkedList()
my_list.insert_at_start(1)   # 在链表头插入数字1
my_list.append(2)           # 在链表尾部插入数字2