Inversions (Data Structures and Algorithms, and Client Programs from Algorithms by Robert Sedgewick and Kevin Wayne)

java.lang.Object
- dsa.Inversions

```
public class Inversions
extends Object
```
This library to count the number of inversions in an array. An inversion in an array a is a pair (i, j) of indicies such that i < j and a [i] > a[j].

Constructor Summary

Constructors
Constructor Description

Inversions()

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static long`	`count(double[] a)`	Returns the number of inversions in the array `a`.
`static long`	`count(int[] a)`	Returns the number of inversions in the array `a`.
`static long`	`count(Comparable[] a)`	Returns the number of inversions in the array `a`, according to the natural order of its objects.
`static long`	`count(Object[] a, Comparator c)`	Returns the number of inversions in the array `a`, according to the order induced by the comparator `c`.
`static void`	`main(String[] args)`	Unit tests the library.

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

- Constructor Detail
  - Inversions
```
public Inversions()
```
- Method Detail
  - count
```
public static long count(Comparable[] a)
```
    Returns the number of inversions in the array a, according to the natural order of its objects.
    
    Parameters:
    
    a - the array.
    
    Returns:
    
    the number of inversions in the array a, according to the natural order of its objects.
  - count
```
public static long count(Object[] a,
                         Comparator c)
```
    Returns the number of inversions in the array a, according to the order induced by the comparator c.
    
    Parameters:
    
    a - the array.
    
    c - the comparator to determine the order of the array.
    
    Returns:
    
    the number of inversions in the array a, according to the order induced by the comparator c.
  - count
```
public static long count(int[] a)
```
    Returns the number of inversions in the array a.
    
    Parameters:
    
    a - the array.
    
    Returns:
    
    the number of inversions in the array a.
  - count
```
public static long count(double[] a)
```
    Returns the number of inversions in the array a.
    
    Parameters:
    
    a - the array.
    
    Returns:
    
    the number of inversions in the array a.
  - main
```
public static void main(String[] args)
```
    Unit tests the library.
    
    Parameters:
    
    args - the command-line arguments.