[karthickgururaj]

Sorry - I'm not able to understand the post. I fully understand the problem - I ask this question sometimes during interviews - with two bracket characters. Say, () and []. So a string like "([)]" is not correctly balanced.

Some folks try with counters - but that very quickly gets out of hand. I try to prod them to a solution - by giving patterns that will defeat their solutions.

What I'm expecting is that the person can identify that use of stack here, which (and this is my source of confusion here) - is the most natural way to solve this problem. Push when we encounter an opening bracket, pop and match when we encounter a closing bracket. The function is generic, within 10 lines in C, can easily be extended to more bracket characters.

So - what is the point of this post?

[poopchute]

Its a quick intro to computability theory. There is a progression of more and more complicated 'machines' on the way from Finite Automata towards Turing Machines. This article goes over what types of things each machine can and can't solve. Its more of a theoretical topic than a practical one (and why you'll occasionally see silly things like someone implementing a turing machine in powerpoint to show that powerpoint could compute anything)