Heaps algorithm #2475
Heaps algorithm #2475
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| [[]] | ||
| >>> heaps([0]) | ||
| [[0]] | ||
| >>> heaps([-1, 1]) | ||
| [[-1, 1], [1, -1]] | ||
| >>> heaps([1, 2, 3]) | ||
| [[1, 2, 3], [2, 1, 3], [3, 1, 2], [1, 3, 2], [2, 3, 1], [3, 2, 1]] |
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Instead of (or in addition to) manual doctest results, please test this against https://docs.python.org/3/library/itertools.html#itertools.permutations to ensure they both deliver identical results.
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Done. Added one comparison between my algo and itertools permutations. Also outputed my permutations as list of tuples instead of list of lists to match itertools.
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Why the use of set()? Perhaps you should be comparing against
https://docs.python.org/3/library/itertools.html#itertools.combinations or https://docs.python.org/3/library/itertools.html#itertools.combinations_with_replacement
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I use set() since i have to compare the result of a generator (itertools) vs mine (list of tuple), as well as the order of tuples might also be different from one version to the other but can still be correct. Maybe you see another "cleaner" way of doing this ?
I don't think comparing with combinations is a good idea, the Heap's algorithm outputs permutations (order of elements matters).
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tuple(permutations(data)) and if that does not work sorted(permutations(data))
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Used sorted() but had to used it on both permutations() and heaps().
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Updated with your comment relative to the iterative version.
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Hey @grochedix, TravisCI finished with status TravisBuddy Request Identifier: 9d04df70-01b6-11eb-9be6-0d9634a5fbe7 |
* heaps_algorithm: new algo * typo * correction doctest * doctests: compare with itertools.permutations * doctest: sorted instead of set * doctest * doctest * rebuild
* heaps_algorithm: new algo * typo * correction doctest * doctests: compare with itertools.permutations * doctest: sorted instead of set * doctest * doctest * rebuild
Describe your change:
Added the Heap's algorithm under the "divide and conquer" folder. It outputs all possible permutations from a list of elements.
Checklist:
Fixes: #{$ISSUE_NO}.