Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Yep, 'i' refers to the index of the row as the board is traversed with the 'every' function.
So it's mapping the ith element of each row and passing arrays representing individual columns into checkDigits().
This comment is hidden because it contains spoiler information about the solution