edu.princeton.cs.algs4

Class Insertion

java.lang.Object

edu.princeton.cs.algs4.Insertion

public class Insertion
extends java.lang.Object

The Insertion class provides static methods for sorting an array using insertion sort.

This implementation makes ~ 1/2 n^2 compares and exchanges in the worst case, so it is not suitable for sorting large arbitrary arrays. More precisely, the number of exchanges is exactly equal to the number of inversions. So, for example, it sorts a partially-sorted array in linear time.

The sorting algorithm is stable and uses O(1) extra memory.

See InsertionPedantic.java for a version that eliminates the compiler warning.

For additional documentation, see Section 2.1 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Method Summary

Modifier and Type	Method and Description
static int[]	indexSort(java.lang.Comparable[] a) Returns a permutation that gives the elements in the array in ascending order.
static void	main(java.lang.String[] args) Reads in a sequence of strings from standard input; insertion sorts them; and prints them to standard output in ascending order.
static void	sort(java.lang.Comparable[] a) Rearranges the array in ascending order, using the natural order.
static void	sort(java.lang.Comparable[] a, int lo, int hi) Rearranges the subarray a[lo..hi) in ascending order, using the natural order.
static void	sort(java.lang.Object[] a, java.util.Comparator comparator) Rearranges the array in ascending order, using a comparator.
static void	sort(java.lang.Object[] a, int lo, int hi, java.util.Comparator comparator) Rearranges the subarray a[lo..hi) in ascending order, using a comparator.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

sort

public static void sort(java.lang.Comparable[] a)

Rearranges the array in ascending order, using the natural order.

Parameters:

a - the array to be sorted

sort

public static void sort(java.lang.Comparable[] a,
                        int lo,
                        int hi)

Rearranges the subarray a[lo..hi) in ascending order, using the natural order.

Parameters:

a - the array to be sorted

lo - left endpoint (inclusive)

hi - right endpoint (exclusive)

sort

public static void sort(java.lang.Object[] a,
                        java.util.Comparator comparator)

Rearranges the array in ascending order, using a comparator.

Parameters:

a - the array

comparator - the comparator specifying the order

sort

public static void sort(java.lang.Object[] a,
                        int lo,
                        int hi,
                        java.util.Comparator comparator)

Rearranges the subarray a[lo..hi) in ascending order, using a comparator.

Parameters:

a - the array

lo - left endpoint (inclusive)

hi - right endpoint (exclusive)

comparator - the comparator specifying the order

indexSort

public static int[] indexSort(java.lang.Comparable[] a)

Returns a permutation that gives the elements in the array in ascending order.

Parameters:

a - the array

Returns:

a permutation p[] such that a[p[0]], a[p[1]], ..., a[p[n-1]] are in ascending order

main

public static void main(java.lang.String[] args)

Reads in a sequence of strings from standard input; insertion sorts them; and prints them to standard output in ascending order.

Parameters:

args - the command-line arguments