Write a program that tells you if the expression entered is a

tautology or not. Assume that you have no more than three

propositional symbols in your expressions -- call them P, Q, R.

You must use the linked list implementation of the data

structures needed.

The above is my homework assignment. I am wondering if anyone has any idea where to start with this. I started writing a postfix -> infix linekd list stack example, and then thought I'd edit it, but I'm at a loss as to how you would get the values for the true/value?

Would I have to include the truth tables?