easyCoding4-language solution

Linked List Cycle Detection

Linked List Cycle Detection is a easy coding interview question covering linked list, two pointers — the kind asked at FAANG (Facebook/Meta, Apple, Amazon, Netflix, Google) and AI-first companies like Anthropic, OpenAI, and Nvidia.

linked listtwo pointers

Linked List Cycle Detection — Problem Statement

Given the head of a singly linked list, determine whether the list contains a cycle - using O(1) extra space.

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What's inside this guide

A three-step hint ladder before the solution
A 4-step trace of the code on an example
Solutions in 4 languages: Python, C++, Java and Go
Time and space complexity, stated up front
A written model answer

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The rest of the loop

A full interview loop is more than one round. These are the others, each with what is on the site for it.

Linked List Cycle Detection