The seen array filters out the characters which are available for filling a particular position. The mk array makes sure that we choose only one of the repeated characters.
for example, if the array is aba if mk array is there backtracking will try like String : a _ _ or b _ _ or a _ _ character position : 0 _ _ 1 _ _ 2 _ _ with mk array , String : a _ _ character position : 2 _ _ will not happen. I hope you can get my notations. On Jul 29, 10:17 am, Arun Vishwanathan <[email protected]> wrote: > @amit:i am not clear about the code.Maybe could you take your example string > aabc and explain a few steps that happen from your code??.The array mk is > locally created for each function call and so I do not get how it keeps > track of elements tried cos each time it is a new array. > > On Fri, Jul 29, 2011 at 3:54 AM, amit karmakar > <[email protected]>wrote: > > > > > What my recursive solution does is that, > > For all elements that can be used at position *k*, fix that element at > > position *k* and then permute the rest of the elements. > > So if are two same elements which can be used at position *k* we must > > choose only one of it to avoid repeated permutations. > > > Array mk[256] keeps a track of the elements that have already been > > tried. > > > >> Does there exist any better solution also, or this backtracking solution > > is the best? > > You should have a look at this: > > >http://en.wikipedia.org/wiki/Permutation#Algorithms_to_generate_permu... > > > On Jul 29, 12:34 am, Nitish Garg <[email protected]> wrote: > > > Can you please explain what is the use of the array mk[256], how this > > array > > > solves the problem of repeated characters. > > > Does there exist any better solution also, or this backtracking solution > > is > > > the best? > > > -- > > You received this message because you are subscribed to the Google Groups > > "Algorithm Geeks" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > >http://groups.google.com/group/algogeeks?hl=en. -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
