Check if two singly linked lists intersect:
https://blog.csdn.net/tianyunzqs/article/details/48413165
Best way: O(max[mn])
If the two singly linked lists are both acyclic singly linked lists, connect the first position of one of the singly linked lists, and then judge whether the other singly linked list has a cycle. If there is a cycle, it means that the two singly linked lists intersect.
If one has a cycle and one does not, the two singly linked lists do not intersect.
If both singly linked lists have loops, check whether the positions of the loop connection points are the same.
Check if a singly linked list has a cycle
Determine the position of the connection point of a singly linked list with a ring
Determining the ring length of a singly linked watch with a ring
Determine the total length of a singly linked list with a ring
https://www.cnblogs.com/xudong-bupt/p/3667729.html