Talk:Permutations by swapping: Difference between revisions
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(What is the task again?) |
(→Does "Python: recursive" fit this task?: successive items by a swap between two items plus give the sign.) |
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::So the order of the output doesn't matter, as long as it is true that adjacent results differ by a swap of adjacent elements? How would one verify this easily? Perhaps a function to verify that the results satisfy this should be a part of the task, because it is insufficient to simply show that all the permutations are generated. --[[User:Spoon!|Spoon!]] 00:07, 3 August 2012 (UTC) |
::So the order of the output doesn't matter, as long as it is true that adjacent results differ by a swap of adjacent elements? How would one verify this easily? Perhaps a function to verify that the results satisfy this should be a part of the task, because it is insufficient to simply show that all the permutations are generated. --[[User:Spoon!|Spoon!]] 00:07, 3 August 2012 (UTC) |
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:::Well: |
:::Well: |
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:::* If the items doesn't change. (Sort them and compare). |
:::* If the items (of each successive perm), doesn't change. (Sort them and compare). |
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:::* And if exactly two items are not in the same position as before. |
:::* And if exactly two items are not in the same position as before. |
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:::* Then the two consecutive permutations are OK. |
:::* Then the two consecutive permutations are OK. |
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:::--[[User:Paddy3118|Paddy3118]] 07:35, 3 August 2012 (UTC) |
:::--[[User:Paddy3118|Paddy3118]] 07:35, 3 August 2012 (UTC) |
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:::: This is confusing. If the task is to use the Steinhaus–Johnson–Trotter algorithm then the permutations must appear in a specific order. If the task is to find the parity of a permutation, then we do not need the Steinhaus–Johnson–Trotter algorithm. So... what's the task? --[[User:Rdm|Rdm]] 07:58, 3 August 2012 (UTC) |
:::: This is confusing. If the task is to use the Steinhaus–Johnson–Trotter algorithm then the permutations must appear in a specific order. If the task is to find the parity of a permutation, then we do not need the Steinhaus–Johnson–Trotter algorithm. So... what's the task? --[[User:Rdm|Rdm]] 07:58, 3 August 2012 (UTC) |
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:::::That particular ''algorithm'' is given as an example, but you are free to use another that fits the requirements. In the explanations I read of the SJT algorithm, they mentioned swapping quite a lot - hence the task title. |
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== bear in mind? == |
== bear in mind? == |
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