仅使用一个函数在不同索引中插入链表中的元素

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

class LinkedList:
    def __init__(self):
        self.head = None

    def insert_at_index(self, index, data):
        new_node = Node(data)
        if index == 0:
            new_node.next = self.head
            self.head = new_node
            return

        current = self.head
        previous = None
        current_index = 0

        while current and current_index < index:
            previous = current
            current = current.next
            current_index += 1

        if current_index == index:
            new_node.next = current
            previous.next = new_node
        else:
            raise IndexError("Index out of range")

    def print_list(self):
        current = self.head
        while current:
            print(current.data, end=" -> ")
            current = current.next
        print("None")

# 示例用法
llist = LinkedList()
llist.head = Node(1)
second = Node(2)
third = Node(4)

llist.head.next = second
second.next = third

print("原始链表:")
llist.print_list()

llist.insert_at_index(2, 3)
print("插入元素后的链表:")
llist.print_list()