java的三种排序算法

public class SortDemo {

//  Java的三种排序算法：选择排序，冒泡排序，插入排序。

public static void main(String[] args) {

int[] ary = { 3, 1, 4, 9, 2, 5, 6,4 };

selectionSort(ary);

System.out.println(Arrays.toString(ary));

bubbleSort(ary);

System.out.println(Arrays.toString(ary));

insertionSort(ary);

System.out.println(Arrays.toString(ary));

}

/** 插入式排序 */

public static void insertionSort(int[] ary) {

int i, j, k;

for (i = 1; i < ary.length; i++) {

k = ary[i];// 取出

// 查找位置

for (j = i - 1; j >= 0 && k < ary[j]; j--) {

ary[j + 1] = ary[j];// 向后移动元素

}

ary[j + 1] = k;// 插入

}

}

/** 冒泡排序 */

public static void bubbleSort(int[] ary) {

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

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

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

int t = ary[j];

ary[j] = ary[j + 1];

ary[j + 1] = t;

}

}

}

}

/** 选择排序: 每轮选择一个最小的放到前面 */

public static void selectionSort(int[] ary) {

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

for (int j = i + 1; j < ary.length; j++) {

if (ary[i] > ary[j]) {

int t = ary[i];

ary[i] = ary[j];

ary[j] = t;

}

}

}

}

}