Permutations

I suggest doing a coding challenge on generating permutations of an array. That can easily be done beautifully and the intuition of the algorithms is usually pretty straightforward. Namely, I'd love to see
- Fisher-Yates shuffle (https://bost.ocks.org/mike/shuffle/)
- Heap's algorithm (http://ruslanledesma.com/2016/06/17/why-does-heap-work.html)
- Next permutation lexicographically (https://www.nayuki.io/page/next-lexicographical-permutation-algorithm)
- And my challenge to you is devise some way of generating permutations of bits of an integer. (That, actually, was the problem which made me research all aforementioned algorithms.)

Inizia esaminando i riferimenti collegati nell'issue relativi a Fisher-Yates shuffle, Heap's algorithm e next lexicographical permutation. Chiarisci quali approcci alla permutazione e quale sfida sui bit degli interi debbano essere inclusi, quindi definisci il formato didattico e i criteri di completamento prima di iniziare il lavoro.

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