Combinations.LexicographicIterator

java.lang.Object
- org.apache.commons.numbers.combinatorics.Combinations.LexicographicIterator

All Implemented Interfaces:

java.util.Iterator<int[]>

Enclosing class:

Combinations
```
private static class Combinations.LexicographicIterator
extends java.lang.Object
implements java.util.Iterator<int[]>
```
Lexicographic combinations iterator.
Implementation follows Algorithm T in The Art of Computer Programming Internet Draft (PRE-FASCICLE 3A), "A Draft of Section 7.2.1.3 Generating All Combinations, D. Knuth, 2004.

The degenerate cases k == 0 and k == n are NOT handled by this implementation. It is assumed that n > k > 0.

Field Summary

Fields
Modifier and Type	Field	Description
`private int[]`	`c`	c[1], ..., c[k] stores the next combination; c[k + 1], c[k + 2] are sentinels.
`private int`	`j`	Marker: smallest index such that `c[j + 1] > j`.
`private int`	`k`	Size of subsets returned by the iterator.
`private boolean`	`more`	Return value for `hasNext()`.

Constructor Summary

Constructors
Constructor Description

LexicographicIterator(int n, int k)
Construct a CombinationIterator to enumerate k-sets from a set of size n.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type Method Description

boolean hasNext()

int[] next()

void remove()
Not supported.
- Methods inherited from class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
- Methods inherited from interface java.util.Iterator
  forEachRemaining

- Field Detail
  - k
```
private final int k
```
    Size of subsets returned by the iterator.
  - c
```
private final int[] c
```
    c[1], ..., c[k] stores the next combination; c[k + 1], c[k + 2] are sentinels.
    Note that c[0] is "wasted" but this makes it a little easier to follow the code.
  - more
```
private boolean more
```
    Return value for hasNext().
  - j
```
private int j
```
    Marker: smallest index such that c[j + 1] > j.
- Constructor Detail
  - LexicographicIterator
```
LexicographicIterator(int n,
                      int k)
```
    Construct a CombinationIterator to enumerate k-sets from a set of size n.
    NOTE: It is assumed that n > k > 0.
    
    Parameters:
    
    n - Size of the set from which subsets are enumerated.
    
    k - Size of the subsets to enumerate.
- Method Detail
  - hasNext
```
public boolean hasNext()
```
    Specified by:
    
    hasNext in interface java.util.Iterator<int[]>
  - next
```
public int[] next()
```
    Specified by:
    
    next in interface java.util.Iterator<int[]>
  - remove
```
public void remove()
```
    Not supported.
    
    Specified by:
    
    remove in interface java.util.Iterator<int[]>