Given a bitstring generate all bitstring with n flipped bits












1












$begingroup$


For an algorithm I need to be able to iterate over all bit strings where $k$ bits are flipped given a bit string with length $n$ and $n geq k$. For instance let's say I have the bit string $1001$ and I want to have all bit strings with $2$ bits flipped. That should result in the following bit strings:



1010
1100
1110
0000
0011
0101


So given a bit string of length $n$ and where $k$ bits will be flipped the result will be $binom{n}{k}$ bit strings. Is there an efficient way to generate all of them? The bit strings I have as input are just unsigned integers so I can use bit twiddling!










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    1












    $begingroup$


    For an algorithm I need to be able to iterate over all bit strings where $k$ bits are flipped given a bit string with length $n$ and $n geq k$. For instance let's say I have the bit string $1001$ and I want to have all bit strings with $2$ bits flipped. That should result in the following bit strings:



    1010
    1100
    1110
    0000
    0011
    0101


    So given a bit string of length $n$ and where $k$ bits will be flipped the result will be $binom{n}{k}$ bit strings. Is there an efficient way to generate all of them? The bit strings I have as input are just unsigned integers so I can use bit twiddling!










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      For an algorithm I need to be able to iterate over all bit strings where $k$ bits are flipped given a bit string with length $n$ and $n geq k$. For instance let's say I have the bit string $1001$ and I want to have all bit strings with $2$ bits flipped. That should result in the following bit strings:



      1010
      1100
      1110
      0000
      0011
      0101


      So given a bit string of length $n$ and where $k$ bits will be flipped the result will be $binom{n}{k}$ bit strings. Is there an efficient way to generate all of them? The bit strings I have as input are just unsigned integers so I can use bit twiddling!










      share|cite|improve this question









      $endgroup$




      For an algorithm I need to be able to iterate over all bit strings where $k$ bits are flipped given a bit string with length $n$ and $n geq k$. For instance let's say I have the bit string $1001$ and I want to have all bit strings with $2$ bits flipped. That should result in the following bit strings:



      1010
      1100
      1110
      0000
      0011
      0101


      So given a bit string of length $n$ and where $k$ bits will be flipped the result will be $binom{n}{k}$ bit strings. Is there an efficient way to generate all of them? The bit strings I have as input are just unsigned integers so I can use bit twiddling!







      algorithms combinatorics bit-manipulation






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      asked Dec 27 '18 at 12:00









      John SmithJohn Smith

      1184




      1184






















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          $begingroup$

          Let your initial bit string be x.



          For all numbers b with k bits set (i.e. where k bits are 1), output x xor b.



          Finding all numbers with k bits set is described elsewhere, for example here






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            1 Answer
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            1 Answer
            1






            active

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            active

            oldest

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            active

            oldest

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            2












            $begingroup$

            Let your initial bit string be x.



            For all numbers b with k bits set (i.e. where k bits are 1), output x xor b.



            Finding all numbers with k bits set is described elsewhere, for example here






            share|cite|improve this answer









            $endgroup$


















              2












              $begingroup$

              Let your initial bit string be x.



              For all numbers b with k bits set (i.e. where k bits are 1), output x xor b.



              Finding all numbers with k bits set is described elsewhere, for example here






              share|cite|improve this answer









              $endgroup$
















                2












                2








                2





                $begingroup$

                Let your initial bit string be x.



                For all numbers b with k bits set (i.e. where k bits are 1), output x xor b.



                Finding all numbers with k bits set is described elsewhere, for example here






                share|cite|improve this answer









                $endgroup$



                Let your initial bit string be x.



                For all numbers b with k bits set (i.e. where k bits are 1), output x xor b.



                Finding all numbers with k bits set is described elsewhere, for example here







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Dec 27 '18 at 12:38









                Albert HendriksAlbert Hendriks

                1,391529




                1,391529






























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