Medium
,Linked List
,Two Pointers
,Hash Table
Given the head
of a linked list, return the node where the cycle begins. If there is no cycle, return null
.
There is a cycle in a linked list if there is some node in the list that can be reached again by continuously following the next
pointer. Internally, pos
is used to denote the index of the node that tail's next
pointer is connected to (0-indexed). It is -1
if there is no cycle. Note that pos
is not passed as a parameter.
Do not modify the linked list.
Example 1:
Example 2:
Example 3:
Constraints:
Node.val
<= 105pos
is -1
or a valid index in the linked-list.Follow up: Can you solve it using O(1) (i.e. constant) memory?
Ron ChenThr, Mar 9, 2023
Yen-Chi ChenThu, Mar 9, 2023
Yen-Chi ChenThu, Mar 9, 2023
MarsgoatThu, Mar 9, 2023