postOrder to preOrder algorithm

Does anyone know of a quick way to convert from postorder to preorder?  We're trying to convert from postorder input of a binary tree traversal, to inorder and preorder.  We've got inorder down, but can't think of a universal way to get to preorder.

P.S. Python sucks for a data structures class.

>>1
>P.S. Python sucks for a data structures class.

WHAT THE FUCK KIND OF SCHOOL USES PYTHON TO TEACH DATA STRUCTURES? Data structures should be taught using C/C++ so that you get a feel for how the structures are actually implemented in the machine, which helps you understand why certain structures have certain algorithmic complexities!

WHAT THE FUCK KIND OF SCHOOL USES PYTHON TO TEACH DATA STRUCTURES‽
Data structures _should be taught using ML/Haskell so that you get a feel for how you can actually mathematically reason about structures, which helps you understand why certain structures have certain algorithmic complexities！