Martin v. Löwis wrote: > Mir Nazim wrote: > > Example Problem: > > > > Generate all possible permutations for > > [1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2] > > > > [1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2] (notice an extra 2 ) > > > > eliminate some combinations based on some conditions and combine the > > rest of combinations. And now generate all possible combinations for > > resulting data set. > > Hope you get the idea. > > Unfortunately, I don't. Why do you have two lists for which to generate > permutations? Why is it important that the second list has an extra 2 > (actually, not extra, but it replaces a 1)? > What are "some conditions" by which to eliminate permutations? > How to "combine" the remaining permutations? > What is the "resulting data set", and what is a "possible combination" > of it?
condition are there cannot be more than 3 consecutive 2's or 1's > If the task is to produce all distinct permutations of 6 occurrences > of 1 and 6 occurrences of 2, I suggest the program below. It needs > produces much fewer than 12! results (namely, 924). > Yes that number I had already worked out and it is 792 for second list. Now I have generated all distinct permutations and after eliminating the permutations based on above condition I am left with 1060 permutations. Now I ahave a lits with 1060 lists in it. Now comes the hard part. How many possible distinct ways are there to arrange 1060 elements taken 96 at a time 1060! / (1060 - 96)! Hope you got the idea, why i need some faster ways to do it. Now out of these i need to test only those lists whose sum of elements(18 or 19) follows a particular pattern. Can Anybody can alternate ways to do it on a Celeron 1.4 Ghz, 256 MB RAM laptop. Thnaks > Regards, > Martin > > numbers = [1,2] > remaining = [None, 6, 6] > result = [None]*12 > > def permutations(index=0): > if index == 12: > yield result > else: > for n in numbers: > if not remaining[n]: > continue > result[index] = n > remaining[n] -= 1 > for k in permutations(index+1): > yield k > remaining[n] += 1 > > for p in permutations(): > print p -- http://mail.python.org/mailman/listinfo/python-list
