交换排序

package test;

public class BubbleSort {

public static void main(String[] args) {

int[] arr = { 91, 55, 18, 39, 47, 62, 48, 16, 4 };

sort(arr);

}

public static void sort(int[] arr) {

//冒泡排序两层循环

int temp;

for (int i = 0; i < arr.length - 1; i++) {

for (int j = 0; j < arr.length -1- i; j++) {

if (arr[j] > arr[j + 1]) {

temp = arr[j];

arr[j] = arr[j + 1];

arr[j + 1] = temp;

}

}

}

for (int k = 0; k < arr.length; k++) {

System.out.print(arr[k]+" ");

}

}

}

package test;

/**快速排序

 * 需要两个函数：

① 递归函数  public static void quickSort(int[]n ,int left,int right)

② 分割函数（一趟快速排序函数） public static int partition(int[]n ,int left,int right)

 * @author Administrator

 *

 */

public class QuickSort {  

  

public static void main(String[] args) {

int [] arr = {49,38,65,97,76,13,27};  

quickSort(arr,0,arr.length-1);

for (int i = 0; i < arr.length; i++) {  

            System.out.print(arr[i]+" ");  

        } 

}

public static void quickSort(int[] arr, int left, int right){

int key; 

if(left<right){

key=partition(arr, left, right);

quickSort(arr, left, key-1);

quickSort(arr, key+1, right);

}

}

//一趟排序

public static int partition(int[] arr, int left, int right){

int key=arr[left];

while(left<right){

while(left<right&&arr[right]>=key) right--;

   arr[left]=arr[right];

   

while(left<right&&arr[left]<=key) left++;

            arr[right]=arr[left];

}

arr[left]=key;

return left;

}

}