Combinations.LexicographicComparator

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

All Implemented Interfaces:

java.io.Serializable, java.util.Comparator<int[]>

Enclosing class:

Combinations
```
private static class Combinations.LexicographicComparator
extends java.lang.Object
implements java.util.Comparator<int[]>, java.io.Serializable
```
Defines a lexicographic ordering of the combinations. The comparison is based on the value (in base 10) represented by the digit (interpreted in base n) in the input array, in reverse order.

Field Summary

Fields
Modifier and Type	Field	Description
`private int`	`k`	Number of elements in each combination.
`private int`	`n`	Size of the set from which combinations are drawn.
`private static long`	`serialVersionUID`	Serializable version identifier.

Constructor Summary

Constructors
Constructor Description

LexicographicComparator(int n, int k)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`compare(int[] c1, int[] c2)`
`private long`	`lexNorm(int[] c)`	Computes the value (in base 10) represented by the digit (interpreted in base `n`) in the input array in reverse order.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator
equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

- Field Detail
  - serialVersionUID
```
private static final long serialVersionUID
```
    Serializable version identifier.
    
    See Also:
    
    Constant Field Values
  - n
```
private final int n
```
    Size of the set from which combinations are drawn.
  - k
```
private final int k
```
    Number of elements in each combination.
- Constructor Detail
  - LexicographicComparator
```
LexicographicComparator(int n,
                        int k)
```
    Parameters:
    
    n - Size of the set from which subsets are selected.
    
    k - Size of the subsets to be enumerated.
- Method Detail
  - compare
```
public int compare(int[] c1,
                   int[] c2)
```
    Specified by:
    
    compare in interface java.util.Comparator<int[]>
    
    Throws:
    
    java.lang.IllegalArgumentException - if the array lengths are not equal to k.
    
    java.lang.IllegalArgumentException - if an element of the array is not within the interval [0, n).
  - lexNorm
```
private long lexNorm(int[] c)
```
    Computes the value (in base 10) represented by the digit (interpreted in base n) in the input array in reverse order. For example if c is {3, 2, 1}, and n is 3, the method will return 18.
    
    Parameters:
    
    c - Input array.
    
    Returns:
    
    the lexicographic norm.
    
    Throws:
    
    java.lang.IllegalArgumentException - if an element of the array is not within the interval [0, n).