You are given an array of strings tokens that represents an arithmetic expression in a Reverse Polish Notation.
tokens
Evaluate the expression. Return an integer that represents the value of the expression.
Given the head of a singly linked list, reverse the list, and return the reversed list.
head
A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.
Given two strings s and t, return true if t is an anagram of s, and false otherwise.
s
t
true
false
An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.