See: Description
Class  Description 

CombinationIterator 
Iterator that returns different combinations of n integers taken k at a time.

FixedSumIterator 
Generates int[] arrays such that the sum of (k+1) * array[k] over the elements
of array are equal to a given value.

PermutationDegenerateIterator 
Iterator that returns unique permutations of an array of integers, with
degeneracy such that some of the integers may appear more than once in the array.

PermutationIterator 
Iterator that returns different permutations of a sequence of integers when
called in successive iterations.
