head, the head of a linked list, determine if the linked list has a cycle in it.
- 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
posis used to denote the index of the node that tail’s
nextpointer is connected to. Note that
posis not passed as a parameter.
trueif there is a cycle in the linked list. Otherwise, return
- This challenge corresponds to LeetCode #141.
- The number of the nodes in the list is in the range
-105 <= Node.val <= 105
-1or a valid index in the linked-list.
Input: head = [3, 2, 0, -4], pos = 1 Output: true Explanation: There is a cycle in the linked list, where the tail connects to the 1st node (0-indexed).
Input: head = [1, 2], pos = 0 Output: true Explanation: There is a cycle in the linked list, where the tail connects to the 0th node.
Input: head = , pos = -1 Output: false Explanation: There is no cycle in the linked list.
Below is my solution and some test cases. This solution has a linear time complexity O(n) and a constant space complexity O(1), where n is the length of the linked list.