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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.
Maybe because you mutated the input? test [North, East, South, West] should be [North, East, South, West].
Interesting task, but meaningless in this formulation. From the point of view of logic and common sense, opposite directions always neutralize each other, no matter how far they are in the sequence. You need either at the very beginning to emphasize the lack of logic and point out the features of the solution, or reformulate the task.