010 given a circular linked list, implement an algorithm to return the Start Node of the ring (keep it up)

Given a circular linked list, an algorithm is implemented to return the Start Node of the ring.


Definition:


Cyclic linked list: the pointer of a node in the linked list points to a previous node, resulting in a ring in the linked list.


Example:


Input: A-> B-> C-> D-> E-> C [node C has already appeared before]

Output: node C

You can use a Map <node *, bool> to solve the problem.

The following is a strange solution to the beauty of programming: fast and slow pointer solution.

Code:

Struct snode {int data; snode * Next;}; snode * findcirlestart (const snode * vhead) {If (vhead-> next = NULL) return NULL; snode * fast = vhead; snode * slow = vhead; while (slow & fast-> next) {slow = slow-> next; fast = fast-> next; if (slow = fast) break;} slow = vhead; while (slow! = Fast) {slow = slow-> next; fast = fast-> next;} Return fast ;}

010 given a circular linked list, implement an algorithm to return the Start Node of the ring (keep it up)