Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.

Given a singly linked list, determine if it is a palindrome.

Remove all elements from a linked list of integers that have value val.

Reverse a singly linked list.

Write a program to find the node at which the intersection of two singly linked lists begins.

Given a linked list, return the node where the cycle begins. If there is no cycle, return null.

Given a linked list, determine if it has a cycle in it.

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

Given a sorted linked list, delete all duplicates such that each element appear only once.