[algogeeks] Re: Finding the distance between two permutations of a string of length N

2006-05-18 Thread Deepak Babu
Vishnu, How about replacing your map with a hashtable and you get o(n) complexity ?! - DeepakOn 5/18/06, vishnu priya [EMAIL PROTECTED] wrote: Let the string be str1.Sort that string and form a map of sorted string and their positions in the original string . example :consider string

[algogeeks] Re: Finding the distance between two permutations of a string of length N

2006-05-15 Thread pramod
Isn't this same as permuting 1,2,...,n to get p1,p2,...,pn ? Using an auxiliary array of bools we can find out the number of permutations in O(n) time right? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups

[algogeeks] Re: Finding the distance between two permutations of a string of length N

2006-05-15 Thread aj
For the sake of simplicity assume that one permutation is identity permutation and the other one is pi. Write pi as product of disjoint cycles, which can be done in O(n) time. If the number of disjoint cycles is k, then the distance between identity permutation and pi is (n - k). Proof of

[algogeeks] Re: Finding the distance between two permutations of a string of length N

2006-05-14 Thread Vishal
I am not sure whether somebody has already replied to this problem.Here we assume -n = number of chars which are out of place in the permutationsN = actual length of string.Let's define perfect swap as the swap in which both the characters are placed at the desired location. For a string with n