{"id":638,"date":"2025-07-15T12:39:59","date_gmt":"2025-07-15T07:09:59","guid":{"rendered":"https:\/\/codeanddebug.in\/blog\/?p=638"},"modified":"2025-07-15T12:40:00","modified_gmt":"2025-07-15T07:10:00","slug":"linked-list-cycle-leetcode-141","status":"publish","type":"post","link":"https:\/\/codeanddebug.in\/blog\/linked-list-cycle-leetcode-141\/","title":{"rendered":"Linked List Cycle | Leetcode 141 | Floyd’s Cycle Detection"},"content":{"rendered":"\n

Given\u00a0head<\/code>, the head of\u00a0a linked list, determine if the\u00a0linked list has a cycle\u00a0in it. There is\u00a0a cycle in a linked list if there is some node\u00a0in the list that can\u00a0be reached again by continuously\u00a0following the\u00a0next<\/code>\u00a0pointer. Return\u00a0true<\/code>\u00a0if there is a\u00a0cycle in the linked list,\u00a0otherwise return\u00a0false<\/code>.<\/p>\n\n\n\n

Here’s the [Problem Link<\/span><\/mark><\/a><\/strong>] to begin with.<\/p>\n\n\n\n

Example 1:<\/strong><\/p>\n\n\n\n

\"\"\/<\/figure>\n\n\n\n
Input:<\/strong> head = [3,2,0,-4], pos = 1
Output:<\/strong> true
Explanation:<\/strong> There is a cycle in the linked list, where the tail connects to the 1st node (0-indexed).<\/pre>\n\n\n\n
Example 2:<\/strong><\/p>\n\n\n\n
\"\"\/<\/figure>\n\n\n\n
Input:<\/strong> head = [1,2], pos = 0
Output:<\/strong> true
Explanation:<\/strong> There is a cycle in the linked list, where the tail connects to the 0th node.<\/pre>\n\n\n\n
Example 3:<\/strong><\/p>\n\n\n\n
\"\"\/<\/figure>\n\n\n\n
Input:<\/strong> head = [1], pos = -1
Output:<\/strong> false
Explanation:<\/strong> There is no cycle in the linked list.<\/pre>\n\n\n\n
Constraints:<\/strong><\/p>\n\n\n\n