Group items tagged

def comb(items, n=None): if n is None: n = len(items) for i in range(len(items)): v = items[i:i+1] if n == 1: yield v else: rest = items[i+1:] for c in comb(rest, n-1): yield v + c

def perm(items, n=None): if n is None: n = len(items) for i in range(len(items)): v = items[i:i+1] if n == 1: yield v else: rest = items[:i] + items[i+1:] for p in perm(rest, n-1): yield v + p

Permutation and Combination Enumerator

""" a class for generating permutations from an array # choose 2 letters from 'abcd' c = Chooser(['a', 'b', 'c', 'd'], 2) while c.hasMoreElements(): print c.next() """ import time, copy class NoMoreChoices(StandardError): pass class Chooser:

>     Generate all ways to place n indistiguishable items into k >     distinguishable boxes

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