Linked List Cycle
Explore how to detect cycles in a linked list by using fast and slow pointers. Learn to identify if a list revisits nodes, and implement solutions that return true if a cycle exists and false otherwise. Develop skills to solve linked list cycle problems commonly asked in coding interviews.
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Statement
Given the head of a linked list, determine whether the list contains a cycle. A cycle exists if a node in the list can be revisited by continuously following the next pointers. Return TRUE if a cycle is present; otherwise, return FALSE.
Constraints:
Let n be the number of nodes in a linked list.
-
n -
Node.Value
Examples
Understand the problem
Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:
Linked List Cycle
What is the output if the following linked list is given as an input?
TRUE
FALSE
Figure it out!
We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.
Try it yourself
Implement your solution in the following coding playground.
// The first input of the test case is an array of values representing a linked list.// The second input is the index where the tail connects to form a cycle (or −1 if there's no cycle).// This index is used only to construct the linked list and is not passed to the function.// Definition for a Linked List node// type ListNode struct {// Val int// Next *ListNode// }package mainimport (. "golang-test-code/ds_v1/LinkedList")func detectCycle(head *ListNode) bool {// Replace this placeholder return statement with your codereturn false}