Linked List Cycle — Easy Coding Interview Question

Given the head of a linked list, determine if the linked list has a cycle in it. pos denotes the index the tail connects back to (-1 means no cycle). Return true if there is a cycle, or false otherwise.

Example

Input: values = [3,2,0,-4], pos = 1

Output: true

Constraints

• The number of nodes is in the range [0, 10⁴]
• -10⁵ ≤ Node.val ≤ 10⁵

Topics & Companies

Topics: linked-list, two-pointers

Asked by: Amazon, Google, Meta, Microsoft, Bloomberg

Optimal Solution Complexity

Time complexity: O(n). Space complexity: O(1).

Practice more

• All DSA Problems
• DSA Patterns