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To answer questions like this you need to have a good way of representing reorderings. Our aim is to introduce you to a useful way of doing this called cycle notation that will help you manipulate these permutations on paper. A permutation takes an ordered set of elements and shuffles them into a new order.
Work through the examples below, and then you should be able to solve our problem.
The picture shows a simple shuffle which can be written as (1 4 3 2) in cycle notation. Think 1 goes to 4, 4 goes to 3, 3 goes to 2, and finally 2 goes back to 1 forming a cycle.
Not every shuffle can be represented with just one cycle. Here are two that require 3 cycles.
There is one special case - the identity shuffle which does nothing. Call this (1).
The permutation (2 3) reorders the second and third elements, leaving everything else unchanged. In the shuffles interactivity this same permutation can appear as different length shuffles like this:
Try using the interactivity to make these permutations:
Now, back to the main question:
Can you write down all the ways that you can reorder the letters in sheffuls to make the word shuffles using the cycle notation?