There are k!n binary strings of length n with k 1s, and (i.n) e."1 k comb n are all such strings. e.g.
4 comb 6 0 1 2 3 0 1 2 4 0 1 2 5 0 1 3 4 0 1 3 5 0 1 4 5 0 2 3 4 0 2 3 5 0 2 4 5 0 3 4 5 1 2 3 4 1 2 3 5 1 2 4 5 1 3 4 5 2 3 4 5 (i.6) e."1 ]4 comb 6 1 1 1 1 0 0 1 1 1 0 1 0 1 1 1 0 0 1 1 1 0 1 1 0 1 1 0 1 0 1 1 1 0 0 1 1 1 0 1 1 1 0 1 0 1 1 0 1 1 0 1 0 1 1 1 0 0 1 1 1 0 1 1 1 1 0 0 1 1 1 0 1 0 1 1 0 1 1 0 1 0 1 1 1 0 0 1 1 1 1 See: http://www.jsoftware.com/jwiki/Essays/Combinations http://www.jsoftware.com/jwiki/Essays/Combination_Index ----- Original Message ----- From: Ralph G Selfridge <[EMAIL PROTECTED]> Date: Monday, August 27, 2007 13:24 Subject: [Jprogramming] Permutations of a sort. To: [email protected] > Here's my problem. I have a binary string, potentially long, in > my case > 28. I need to get all binary strings with a specified number of > 1s. I doubt > I can get them all at once, too many, so how do I get from one > to the next? > > What next means is irrelvant, just so I get them with no > duplicates if I > run long emough. > > While I have an answer, I'm curious to see if there is a better way. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
