You’re interviewing for a backend or data engineering role at a FAANG-level company. The interviewer describes a real product scenario:
A large-scale backend system processes ordered data streams stored as singly linked lists. In certain workflows such as data validation, fraud detection, or consistency checks, the system needs to verify whether a sequence of values reads the same forward and backward.
Because the data is stored in a linked list rather than an array, random access is not available. The platform expects an efficient solution that checks whether the list forms a palindrome without unnecessary memory usage.
This is a common practice coding problem for DSA question might ask in Google, Amazon, Netflix, Meta, Apple, Microsoft, Uber, and Bloomberg interviews.
Your Task
Given the head of a singly linked list, return true if the linked list is a palindrome, or false otherwise.
A linked list is a palindrome if the sequence of node values reads the same forward and backward.
Input Format
head: the head node of a singly linked list
Each node is defined as:
ListNode { int val; ListNode next; }
Output Format
- A boolean value
true if the linked list is a palindromefalse otherwise