Recently, yet another article on the death of email ranin the Register, 'The time has come to ditch email' (which I saw due to a Slashdot article ). As usual, itadvocates replacing SMTP email with something that is more 'secure',whatever exactly this means.

Unfortunately, this misses the fundamental problem of spam:

You want to get email from strangers, but only good strangers.

Telling good strangers from bad strangers is a hard problem, to put itone way. There is no

Consider the problem of implementing a modified LIFO stack that has anadditional O(1) operation called min , that gives back the smallestitem in the stack. For now, let's pretend that Python arrays are O(1)(or that someone has implemented a native queue class); in many respectsthey are as far as Python code is concerned.

The simple implementation is to keep two stacks, the main stack andone that you only push new minimum items onto. Then push and pop aresomething