Java选择排序算法

Java 选择排序算法
选择排序算法详解：http://blog.csdn.net/ysjian_pingcx/article/details/8656048选择排序算法源码免积分下载：http://download.csdn.net/detail/ysjian_pingcx/6794271
序：一个爱上Java最初的想法一直没有磨灭：”分享我的学习成果，不管后期技术有多深，打好基础很重要“。
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工具类Swapper，后期算法会使用这个工具类：

/**
 * One util to swap tow element of Array
 * 
 * @author ysjian
 * @version 1.0
 * @email [e-mail]
 * @QQ 646633781
 * @telephone [phone]
 * @csdnBlog http://blog.csdn.net/ysjian_pingcx
 * @createTime 2013-12-20
 * @copyRight Merit
 */
public class Swapper {

private Swapper() {

}

/**
 * Swap tow elements of the array
 * 
 * @param oneIndex
 *            one index
 * @param anotherIndex
 *            another index
 * @param array
 *            the array to be swapped
 * @exception NullPointerException
 *                if the array is null
 */
public static <T extends Comparable<T>> void swap(int oneIndex,
int anotherIndex, T[] array) {
if (array == null) {
throw new NullPointerException("null value input");
}
checkIndexs(oneIndex, anotherIndex, array.length);
T temp = array[oneIndex];
array[oneIndex] = array[anotherIndex];
array[anotherIndex] = temp;
}

/**
 * Swap tow elements of the array
 * 
 * @param oneIndex
 *            one index
 * @param anotherIndex
 *            another index
 * @param array
 *            the array to be swapped
 * @exception NullPointerException
 *                if the array is null
 */
public static void swap(int oneIndex, int anotherIndex, int[] array) {
if (array == null) {
throw new NullPointerException("null value input");
}
checkIndexs(oneIndex, anotherIndex, array.length);
int temp = array[oneIndex];
array[oneIndex] = array[anotherIndex];
array[anotherIndex] = temp;
}

/**
 * Check the index whether it is in the arrange
 * 
 * @param oneIndex
 *            one index
 * @param anotherIndex
 *            another index
 * @param arrayLength
 *            the length of the Array
 * @exception IllegalArgumentException
 *                if the index is out of the range
 */
private static void checkIndexs(int oneIndex, int anotherIndex,
int arrayLength) {
if (oneIndex < 0 || anotherIndex < 0 || oneIndex >= arrayLength
|| anotherIndex >= arrayLength) {
throw new IllegalArgumentException(
"illegalArguments for tow indexs [" + oneIndex + ","
+ oneIndex + "]");
}
}
}

选择排序算法SelectionSortord：

/**
 * Selection sort order, time complexity is O(n2)
 * 
 * @author ysjian
 * @version 1.0
 * @email [e-mail]
 * @QQ 646633781
 * @telephone [phone]
 * @csdnBlog http://blog.csdn.net/ysjian_pingcx
 * @createTime 2013-12-31
 * @copyRight Merit
 * @since 1.5
 */
public class SelectionSortord {

private static final SelectionSortord INSTANCE = new SelectionSortord();

private SelectionSortord() {
}

/**
 * Get the instance of SelectionSortord, only just one instance
 * 
 * @return the only instance
 */
public static SelectionSortord getInstance() {
return INSTANCE;
}

/**
 * Sort the array of <code>int</code> with selection sort order
 * 
 * @param array
 *            the array of int
 */
public void doSort(int... array) {
if (array != null && array.length > 0) {
int length = array.length;

// a flag judge whether the array is in order
boolean flag = true;
for (int i = 0; i < length - 1 && flag; i++) {
flag = false; // set the flag false

// set the current index value as minimum in every circulation
int min = i;
for (int j = i + 1; j < length; j++) {

// compare with the value after index i
if (array[min] > array[j]) {
flag = true; // if not in order,set flag true
/*
 * if the value of index j is lower then exchange the
 * minimum value index
 */
min = j;
}
}
if (flag) {

// if has exchange then swap the two elements
Swapper.swap(i, min, array);
}
}
}
}

/**
 * Sort the array of generic <code>T</code> with selection sort order
 * 
 * @param array
 *            the array of generic
 */
public <T extends Comparable<T>> void doSortT(T[] array) {
if (array != null && array.length > 0) {
int length = array.length;
boolean flag = true;
for (int i = 0; i < length - 1 && flag; i++) {
flag = false;
int min = i;
for (int j = i + 1; j < length; j++) {
if (array[min].compareTo(array[j]) > 0) {
flag = true;
min = j;
}
}
if (flag) {
Swapper.swap(i, min, array);
}
}
}
}
}

测试TestSelectionSortord：

/**
 * Test the selection sort order
 * 
 * @author ysjian
 * @version 1.0
 * @email [e-mail]
 * @QQ 646633781
 * @telephone [phone]
 * @csdnBlog http://blog.csdn.net/ysjian_pingcx
 * @createTime 2013-12-31
 * @copyRight Merit
 */
public class TestSelectionSortord {

/**
 * Test
 * 
 * @param args
 */
public static void main(String[] args) {
SelectionSortord selectSort = SelectionSortord.getInstance();
int[] array = { 25, 36, 21, 45, 98, 13 };
System.out.println(Arrays.toString(array));
selectSort.doSort(array);
System.out.println(Arrays.toString(array));
System.out.println("------------------------");
Integer[] arrayT = { 25, 36, 21, 45, 98, 13 };
System.out.println(Arrays.toString(arrayT));
selectSort.doSortT(arrayT);
System.out.println(Arrays.toString(arrayT));
}
}

选择排序算法详解：http://blog.csdn.net/ysjian_pingcx/article/details/8656048选择排序算法源码免积分下载：http://download.csdn.net/detail/ysjian_pingcx/6794271