algoritm special permutation

  • Thread starter Thread starter andrews
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A

andrews

Hi,
I am looking at a algoritm for special permutation with integers like
f.e.
I start with 1,2,3,4,5

and I want the result

1 2 3 4 5
2 3 5 1 4
4 1 2 5 3
5 4 1 3 2
3 5 4 2 1

Some subset where al of the numbers are on different places

Thanks for any response
 
Hi,
I am looking at a algoritm for special permutation with integers like
f.e.
I start with 1,2,3,4,5

and I want the result

1 2 3 4 5
2 3 5 1 4
4 1 2 5 3
5 4 1 3 2
3 5 4 2 1

Some subset where al of the numbers are on different places

Thanks for any response
Click to expand...

The algorithm would be to take each of the items as the starting
element, and pass the remainders as a shorter list to find the
permutations of the shorter list. Take a smaller set, {1, 2, 3}.
Basically, you would keep the {1}, and pass {2, 3} to the permutations
to find the smaller lists permutations {2, 3} and {3, 2}. Now in the
caller you stick those two lists to the back end of {1}, so you have {1,
2, 3}, and {1, 3, 2}. Now you do the same with {2}, appending {1, 3}
and {3, 1}, and {3} appending {1, 2} and {2, 1}. You could implement
the algorithm using recursion, ending the recursion when the size of the
list passed in is one.
 
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