常用排序算法

package dataStructureAndAlgorithm.sort;

/**
* 插入排序
* 		在要排序的一组数中，假设前面(n-1)[n>=2]个数已经是排好序的，现在要
* 		把第N个数插到前面的有序数中，使得这n个数也是排好顺序。
* @author Blossom
*
*/
public class InsertSort {

/**
* 插入排序实现
* @param array
* @return
*
*/
public static int[] insert_sort(int[] array){
for (int i = 0; i < array.length; i++) {
int temp = array[i];
int j = i - 1;
for ( ; j >= 0 && temp < array[j]; j--) {
array[j+1] = array[j]; //将大于temp的值向后移一位
}
array[j+1] = temp;
}
return array;
}

public static void main(String[] args) {
// TODO Auto-generated method stub
int [] array = new int[]{49,38,65,97,76,13,27,49,78,34,12,64,5,4,62,99,98,54,56,17,18,23,34,15,35,25,53,51};
System.out.println("array.length:" + array.length);
System.out.print("排序之前:");
for (int i = 0; i < array.length; i++) {
System.out.print(array[i] + " , ");
}
System.out.println();
array = insert_sort(array);
System.out.println("array.length:" + array.length);
System.out.print("排序之后:");
for (int i = 0; i < array.length; i++) {
System.out.print(array[i] + " , ");
}
}

}

2.希尔排序

<span style="white-space:pre">	</span>算法现将要排序的一组数按某个增量d(n/2,n为要排序数的个数)分成若干组,等组中记录的下标相差d,对每组中全部元素进行直接出肉排序,

然后再用一个较小的增量(d/2)对它进行分组,在每组中再进行直接插入排序.当增量减到1时,进行直接插入排序后,排序完成

<span style="white-space:pre">	</span>Java代码实现

<span style="white-space:pre">	</span><pre name="code" class="java">package dataStructureAndAlgorithm.sort;/*** 希尔排序 算法现将排序的一组数按某个增量d(n/2,n位要排序数的个数)分成若干组，每组中记录的下标相差d,* 对每组中全部元素进行直接插入排序，然后再用一个较小的增量(d/2)对它进行分组，在每组在进行插入排序 。当增量减到1时，进行直接插入排序后，排序完成** @author Blossom**/public class ShellSort {/*** 希尔排序实现** @param array* @return*/public static int[] shell_sort(int[] array) {double arrayLen = array.length;int temp = 0;while (true) {arrayLen = Math.ceil(arrayLen / 2);int len = (int) arrayLen;for (int i = 0; i < len; i++) {for (int j = i + len; j < array.length; i += len) {int n = j - len;temp = array[j];for (; n >= 0 && temp < array; n -= len) {array[n + len] = array;}array[n + len] = temp;}}if (len == 1) {break;}}return array;}public static void main(String[] args) {// TODO Auto-generated method stubint[] array = new int[] { 1, 54, 6, 3, 78, 34, 12, 45, 56, 100 };System.out.print("排序之前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}System.out.println();array = shell_sort(array);System.out.print("排序之后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}}}

package dataStructureAndAlgorithm.sort;/*** 简单排序* 		在要排序的一组数中，宣传最小的一个数与第一个位置的数交换；* 		然后在剩下的数当中在找最小的与第二个位置的数交换，如此循环到倒数第二个数和最后一个数比较为止* @author Blossom**/public class SelectSort {/*** 选择排序实现* @param array* @return*/public static int [] select_sort(int [] array){for (int i = 0; i < array.length; i++) {int tag = i;int temp = array[i];for (int j = i+1; j < array.length; j++) {if (array[j] < temp) {temp = array[j];tag = j;}}array[tag] = array[i];array[i] = temp;}return array;}public static void main(String[] args) {int [] array = new int []{1,54,6,3,78,34,12,45};System.out.print("排序前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}System.out.println();array = select_sort(array);System.out.print("排序后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}}}

package dataStructureAndAlgorithm.sort;/*** 堆排序 堆排序是一种树形选择排序，是对直接选择排序的有效改进* 定义：具有n个元素的序列(h1,h2,...hn)，当且仅当满足(hi>=h2i,hi>=2i+1)或(hi<=h2i,hi<=2i+1)(i=1,2,.* ..,n/2) 时称之为堆。* 由堆的定义可以看出，堆顶元素(即第一个元素)必须为最大项。完全二叉树可以很直观的表示堆的结构，堆订为根，其它为左子树，右子树，* 初始时把要排序的数的序列看作是一颗顺序存储的二叉树，调整它们的存储序，使之成为一个堆，这时堆的根节点的数最大。* 然后将根节点与堆的最后一个节点交换。然后对前面(n-1)个数重新调整使之成为堆。依次类推，直到只有两个节点的堆，并对他们交换* ，最后得到n个节点的有序序列，* 从算法的描述来看，堆排序需要两个过程，一是建立堆，二是堆订与堆的最后一个元素交换位置。所以堆排序有两个函数组成，一是建堆的渗透函数，* 二是反复调用渗透函数实现排序的函数。** @author Blossom**/public class HeapSort {// 堆排序实现public static int[] heap_sort(int[] array) {int arrayLength = array.length;// 循环建立堆for (int i = 0; i < arrayLength - 1; i++) {// 建立堆buildMaxHeap(array, arrayLength - 1 - i);// 交换堆顶和最后一个元素swap(array, 0, arrayLength - 1 - i);}return array;}private static void swap(int[] array, int i, int j) {int temp = array[i];array[i] = array[j];array[j] = temp;}/*** 对array数组从0到i建大顶堆** @param array* @param i*/private static int[] buildMaxHeap(int[] array, int i) {// 从i处节点(最后一个节点)的父节点开始for (int j = 0; j < array.length; j++) {// j保证正在判断的节点int k = i;// 如果当前k节点的子节点存在while (k * 2 + 1 <= i) {// k节点的左子节点的索引int biggerIndex = 2 * k + 1;// 如果biggerIndex小于i，即biggerIndex+1代表的k节点的右子节点存在if (biggerIndex < i) {// 如果右子节点的值较大if (array[biggerIndex] < array[biggerIndex + 1]) {// biggerIndex总是记录较大子节点的索引biggerIndex++;}}// 如果k节点的值小于其较大的子节点的值if (array[k] < array[biggerIndex]) {// 交换它们swap(array, k, biggerIndex);// 将biggerIndex赋予k,开始while循环的下一次循环，从新保证k节点的值大于其左右子节点的值k = biggerIndex;} else {break;}}}return array;}// 测试public static void main(String[] args) {int[] array = new int[] { 49, 38, 65, 97, 76, 13, 27, 49, 78, 34, 12, 64, 5, 4, 62, 99, 98, 54, 56, 17, 18, 23,34, 15, 35, 25, 53, 51 };System.out.print("排序前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}System.out.println();array = heap_sort(array);System.out.print("排序后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}}}

package dataStructureAndAlgorithm.sort;/*** 冒泡排序* 		在排序的一组数中，对当前的还未排好序的范围内的全部数，自上而下对相邻两个数依次进行比较和调整，让较大* 		的数往下沉，较小的往上冒。即：每当两相邻的数比较后发现它们的排序与排序要求相反时，就将它们互换。* @author Blossom**/public class BubbleSort {/*** 冒泡排序实现* @param array* @return*/public static int [] bubble_sort(int [] array){for (int i = 0; i < array.length; i++) {for (int j = 0; j < array.length-1-i; j++) {if (array[j] > array[j+1]) {int temp = array[j];array[j] = array[j+1];array[j+1] = temp;}}}return array;}public static void main(String[] args) {// TODO Auto-generated method stubint [] array = new int []{49,38,65,97,76,13,27,49,78,34,12,64,5,4,62,99,98,54,56,17,18,23,34,15,35,25,53,51};System.out.print("排序前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i]+" , ");}System.out.println();array = bubble_sort(array);System.out.print("排序后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i]+" , ");}}}

package dataStructureAndAlgorithm.sort;/*** 快速排序 选择一个季遵元素，通常选择第一个元素或者最后一个元素，通过一趟扫描，将待排序列分成两部分，一部分* 比基准元素小，一部分大于等于基准元素，次数基准元素在其排好序后的正确位置，然后再用同样的方法递归的排序划分的两部分.** @author Blossom**/public class QuickSort {public static int[] quick_sort(int[] array, int low, int high) {if (low < high) {int middle = getMiddle(array, low, high);quick_sort(array, low, middle - 1); // 对低字表进行递归排序quick_sort(array, middle + 1, high); // 对高字表进行递归排序}return array;}private static int getMiddle(int[] array, int low, int high) {int temp = array[low]; // 数组的第一个作为中轴while (low < high) {while (low < high && array[high] >= temp) {high--;}array[low] = array[high]; // 比中轴小的记录移到低端while (low < high && array[low] <= temp) {low++;}array[high] = array[low]; // 比中轴大的记录移到高端}array[low] = temp; // 中轴记录到尾return low; // 返回中轴位置}public static int[] sort(int[] array) {if (array.length > 0) {quick_sort(array, 0, array.length - 1);}return array;}// 测试public static void main(String[] args) {// TODO Auto-generated method stubint[] array = new int[] { 49, 38, 65, 97, 76, 13, 27, 49, 78, 34, 12, 64, 5, 4, 62, 99, 98, 54, 56, 17, 18, 23,34, 15, 35, 25, 53, 51 };System.out.print("排序前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}System.out.println();array = sort(array);System.out.print("排序后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}}}

package dataStructureAndAlgorithm.sort;/*** 归并排序* 		归并排序法是将两个(或两个以上)有序集合表合并成一个新的有序表，即把待排序序列分为若干个子序列，* 		每个子序列是有序的，然后在把有序子序列合并为整体有序序列* @author Blossom**/public class MergeSort {/*** 归并排序实现* @param array* @return*/public static int [] merge_sort(int [] array, int left, int right){if (left < right) {//找出中间索引int center = (left + right)/2;//对左边数组进行递归merge_sort(array, left, center);//对右边数组进行递归merge_sort(array, center+1, right);//合并数组array = merge(array, left, center,right);}return array;}private static int[] merge(int[] array, int left, int center, int right) {int [] tmpArr = new int[array.length];int mid = center+1;//third记录中间数组的索引int third = left;int temp = left;while(left <= center && mid <=right){//从两个数组中取出最小的放入中间数组if (array[left] <= array[mid]) {tmpArr[third++] = array[left++];}else {tmpArr[third++] = array[mid++];}}//剩余部分依次放入中间数组while (mid < right) {tmpArr[third++] = array[mid++];}while (left<=center) {tmpArr[third++] = array[left++];}//将中间数组的内容复制会原来的数组while(temp <=right){array[temp] = tmpArr[temp++];}return array;}public static void main(String[] args) {// TODO Auto-generated method stubint [] array = new int []{49,38,65,97,76,13,27,49,78,34,12,64,5,4,62,99,98,54,56,17,18,23,34,15,35,25,53,51};System.out.print("排序前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}array = merge_sort(array, 0, array.length-1);System.out.println();System.out.print("排序后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}}}

package dataStructureAndAlgorithm.sort;import java.util.ArrayList;import java.util.List;/*** 基数排序* 		将所有待比较数值统一为同样的数位长度，数位较短额数前面补零，然后，从最低位开始，依次进行一次排序。* 		这样从最低位排序一直到最高位排序完成以后，数列就变成一个有序序列* @author Blossom**/public class RadixSort {@SuppressWarnings({ "rawtypes", "unchecked" })public static int[] radis_sort(int[] array){int max = array[0];for (int i = 0; i < array.length; i++) {if (array[i]>max) {max = array[i];}}int time = 0;//判断位数while(max>0){max /=10;time++;}//建立10个队列List<ArrayList> queue = new ArrayList<>();for(int i=0;i<10;i++){ArrayList<Integer> queue1 = new ArrayList<>();queue.add(queue1);}//进行time次分配和和收集for (int i = 0; i < time; i++) {//分配数组元素for (int j = 0; j < array.length; j++) {//得到数字的第time+1位数int x = array[j]%(int)Math.pow(10, i+1)/(int)Math.pow(10, i);ArrayList<Integer> queue2 = queue.get(x);queue2.add(array[j]);queue.set(x, queue2);}int count = 0;//元素计数器//收集队列元素for(int k=0;k<10;k++){while(queue.get(k).size()>0){ArrayList<Integer> queue3 = queue.get(k);array[count] = queue3.get(0);queue3.remove(0);count++;}}}return array;}public static void main(String[] args) {int [] array = new int []{49,38,65,97,76,13,27,49,78,34,12,64,5,4,62,99,98,54,101,56,17,18,23,34,15,35,25,53,51};System.out.print("排序前:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}System.out.println();array = radis_sort(array);System.out.print("排序后:");for (int i = 0; i < array.length; i++) {System.out.print(array[i] + " , ");}}}