Constructor Detail

• PermutationGenerator

  public 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

• PermutationGenerator

  public PermutationGenerator​(Iterable<E> items)

Method Detail

• reset

  public void reset()

• getTotal

  public BigInteger getTotal()

• hasNext

  public boolean hasNext()

  Specified by:

  hasNext in interface Iterator<E>

• next

  public List<E> next()

  Generate next permutation (algorithm from Rosen p. 284)

  Specified by:

  next in interface Iterator<E>

  Returns:

  the items permuted

• remove

  public void remove()

  Specified by:

  remove in interface Iterator<E>