Is Insert Greatest Common Divisors in Linked List easy or hard?

The problem is rated Medium. The main challenge is correctly manipulating linked list pointers while maintaining traversal order. Once the insertion logic is clear, the GCD calculation using the Euclidean algorithm is straightforward.

Insert Greatest Common Divisors in Linked List Python/Java solution

The Python and Java solutions both follow the same logic: iterate through the linked list, compute the GCD of adjacent node values, create a new node with that value, and insert it between the two nodes. The implementation runs in O(n log V) time and constant extra space.

How to solve Insert Greatest Common Divisors in Linked List in O(n)?

You traverse the linked list once and insert nodes on the fly. For each node and its next node, compute the GCD and create a new node between them by updating pointers. The traversal itself is O(n), while each GCD calculation contributes a small O(log V) factor.

What is the best approach for Insert Greatest Common Divisors in Linked List?

The best approach is iterative traversal of the linked list. For each adjacent pair of nodes, compute the GCD using the Euclidean algorithm and insert a new node between them. This processes each pair exactly once, giving O(n log V) time complexity and O(1) extra space.

Is Insert Greatest Common Divisors in Linked List asked at Google/Amazon/Meta?

This problem represents a common interview pattern involving linked list pointer manipulation combined with basic math operations like GCD. Variations of linked list insertion and number theory operations frequently appear in interviews at companies such as Amazon, Google, and Meta.

What data structure is used in Insert Greatest Common Divisors in Linked List?

The primary data structure is a singly linked list. The algorithm performs pointer manipulation to insert new nodes between existing ones while using the Euclidean algorithm from number theory to compute the greatest common divisor.

What is the time complexity of Insert Greatest Common Divisors in Linked List?

The time complexity is O(n log V), where n is the number of nodes and V is the maximum node value. Each adjacent pair requires a GCD calculation, and the Euclidean algorithm runs in O(log V) time.

Description Solution Video 13:27

2807. Insert Greatest Common Divisors in Linked List

Medium91.4% acceptance4 companies

Given the head of a linked list head, in which each node contains an integer value.

Between every pair of adjacent nodes, insert a new node with a value equal to the greatest common divisor of them.

Return the linked list after insertion.

The greatest common divisor of two numbers is the largest positive integer that evenly divides both numbers.

Example 1:

Input: head = [18,6,10,3]
Output: [18,6,6,2,10,1,3]
Explanation: The 1^st diagram denotes the initial linked list and the 2^nd diagram denotes the linked list after inserting the new nodes (nodes in blue are the inserted nodes).
- We insert the greatest common divisor of 18 and 6 = 6 between the 1^st and the 2^nd nodes.
- We insert the greatest common divisor of 6 and 10 = 2 between the 2^nd and the 3^rd nodes.
- We insert the greatest common divisor of 10 and 3 = 1 between the 3^rd and the 4^th nodes.
There are no more adjacent nodes, so we return the linked list.

Example 2:

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

Constraints: