Package groovy.util
Class PermutationGenerator<E>
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- groovy.util.PermutationGenerator<E>
 
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 public class PermutationGenerator<E> extends Object implements Iterator<List<E>> Systematically generate permutations. Adapted from Java Code by Michael Gilleland (released with no restrictions) using an algorithm described here: Kenneth H. Rosen, Discrete Mathematics and Its Applications, 2nd edition (NY: McGraw-Hill, 1991), pp. 282-284
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Constructor SummaryConstructors Constructor Description PermutationGenerator(Iterable<E> items)PermutationGenerator(Collection<E> items)WARNING: Don't make n too large.
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Method SummaryAll Methods Instance Methods Concrete Methods Modifier and Type Method Description BigIntegergetTotal()booleanhasNext()List<E>next()Generate next permutation (algorithm from Rosen p.voidremove()voidreset()- 
Methods inherited from class java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface java.util.IteratorforEachRemaining
 
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Constructor Detail- 
PermutationGeneratorpublic PermutationGenerator(Collection<E> items) WARNING: Don't make n too large. Recall that the number of permutations is n! which can be very large, even when n is as small as 20 -- 20! = 2,432,902,008,176,640,000 and 21! is too big to fit into a Java long, which is why we use BigInteger instead.- Parameters:
- items- the items to permute
 
 
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Method Detail- 
resetpublic void reset() 
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getTotalpublic BigInteger getTotal() 
 
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