http://en.wikipedia.org/wiki/Catalan_number
On Sun, Oct 21, 2012 at 4:00 PM, Shruti Gupta <fundooshr...@gmail.com>wrote: > if n=1,2,3 n we denote Push by "P" and Pop by "X" > the we can generate following permutations : > > 1) PPPXXX = 321 > 2) PPXXPX = 213 > 3) PXPXPX = 123 > 4) PXPPXX = 132 > 5) PPXPXX = 231 > > conditions : #P's = #X's and At no point, #X's>#P's > > Ques :- Given n elements, find the number of permutations which are > possible and which are not possible. > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to algogeeks@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com. > 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 algogeeks@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
