[cxS]

I'll be getting to work on this here soon.

I have a question though. Are we going to be working on irregularly shaped puzzles, or just square/rectangular ones?

Although irregularly shaped puzzles are standard and add a level of complexity to this challenge, it really doesn't make things a whole lot more difficult if you know how to think about this in layers. For instance, you could be naive, and have a value of some arbitrary, and unusable number to indicate a block doesn't take up that space for a representation of all squares that are missing in an irregular shape (and make the junk value a special case in your logic), or you could use a dictionary-like container that the STL provides to encapsulate a row, and have an integer paired up with that row that tells you how far over (index-wise) the starting number is from the row with the left-most row's first block's index.