Permutations by swapping: Difference between revisions

let ni = [|for n in N -> 0|]

let gel = Array.length(N)-1

let rec _Ni g e l = seq{

match (l,g) with

|_ when l<0 -> gn.[g] <- -gn.[g]; yield! _Ni (g-1) e (ni.[g-1] + gn.[g-1])

|_ when l=g+1 -> gn.[g] <- -gn.[g]; yield! _Ni (g-1) (e+1) (ni.[g-1] + gn.[g-1])

|_ -> let n = N.[g-ni.[g]+e];

ni.[g] <- l; yield! _Ni gel 0 (ni.[gel] + gn.[gel])}

yield! _Ni gel 0 1

{{out}}

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