Write a Java program to find the factorial of a number.
Create a simple HTML form with validation for email and password.
Implement a binary search algorithm in C++.
Implement a Linked List data structure with methods to add, remove, and find elements.
Implement a solution for the 'Valid Parentheses' problem: Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if open brackets are closed by the same type of brackets, and open brackets are closed in the correct order.