Insert Greatest Common Divisors in Linked List

lcpy gen -n 2807   # by problem number
lcpy gen -s insert_greatest_common_divisors_in_linked_list   # by problem name

Input: head = [18,6,10,3]
Output: [18,6,6,2,10,1,3]
Explanation:
- We insert the greatest common divisor of 18 and 6 = 6 between the 1st and the 2nd nodes.
- We insert the greatest common divisor of 6 and 10 = 2 between the 2nd and the 3rd nodes.
- We insert the greatest common divisor of 10 and 3 = 1 between the 3rd and the 4th nodes.
There are no more adjacent nodes, so we return the linked list.

Input: head = [7]
Output: [7]
Explanation: The 1st diagram denotes the initial linked list and the 2nd diagram denotes the linked list after inserting the new nodes.
There are no pairs of adjacent nodes, so we return the initial linked list.

from math import gcd

from leetcode_py import ListNode


class Solution:
    # Time: O(n)
    # Space: O(1)
    def insert_greatest_common_divisors(self, head: ListNode[int] | None) -> ListNode[int] | None:
        current = head
        while current and current.next:
            inserted = ListNode[int](gcd(current.val, current.next.val))
            inserted.next = current.next
            current.next = inserted
            current = inserted.next
        return head