iframe-proxy | Sunbelt Computer Software

34 lines (28 loc) · 692 Bytes

// @saorav21994

// TC : O(n)

// Sc : O(1)

/**

* Definition for singly-linked list.

* class ListNode {

* int val;

* ListNode next;

* ListNode(int x) {

* val = x;

* next = null;

* }

public class Solution {

public boolean hasCycle(ListNode head) {

if (head == null || head.next == null) return false;

ListNode slow = head;

ListNode fast = head;

while (fast != null && fast.next != null) {

slow = slow.next;

fast = fast.next;

if (fast != null) fast = fast.next;

if (slow == fast) return true;

}

return false;

}

Sunbelt Computer Software