Intersection of Linked List Problem

You are provided with two singly linked lists containing integers, where both lists converge at some node belonging to a third linked list.

Your task is to determine the data of the node at which they start merging. If no merging occurs, return -1.

Example:

The linked lists are structured as follows:

First Linked List: a1, a2, c1
Second Linked List: b1, b2, b3, c1
Third Linked List where merging occurs: c1, c2, c3

An image shows the merging:

Input:

Three lines representing three singly linked lists.
Each line contains elements separated by spaces, ending with -1.
Line 1 (First linked list): a1, a2, ...an, c1, -1
Line 2 (Second linked list): b1, b2, ...bm, c1, -1
Line 3 (Third linked list): c2, c3, ...ck, -1

Output:

A single integer representing the data of the node where the merging starts. Output -1 if no merging occurs.
You don't need to print this yourself as it is managed automatically.

Constraints:

• 0 ≤ N ≤ 10⁵
• 0 ≤ M ≤ 10⁵
• 0 ≤ K ≤ 10⁵
• -10⁹ ≤ data ≤ 10⁹ and data ≠ -1
• Time Limit: 1 second