一、冒泡排序

package com.zhk.code.study;import java.util.Arrays;public class Bubble {/*对数组a中的元素进行排序*/public static void sort(Comparable[] a){for(int i=a.length-1;i>0;i--){for (int j = 0; j <i; j++) {if (greater(a[j],a[j+1])){exch(a,j,j+1);}}}}/*比较v元素是否大于w元素*/private static boolean greater(Comparable v,Comparable w){return v.compareTo(w)>0;}/*数组元素i和j交换位置*/private static void exch(Comparable[] a,int i,int j){Comparable t = a[i];a[i]=a[j];a[j]=t;}//测试代码public static void main(String[] args) {Integer[] a = {4, 5, 6, 3, 2, 1};Bubble.sort(a);System.out.println(Arrays.toString(a));}
}

二、优化

第二层循环完毕如果没有更改位置，那么就证明现在顺序是正确的，就不往下面循环了

package com.zhk.code.study;import java.util.Arrays;public class Bubble {/*对数组a中的元素进行排序*/public static void sort(Comparable[] a){Boolean isSkip = true;for(int i=a.length-1;i>0;i--){for (int j = 0; j <i; j++) {if (greater(a[j],a[j+1])){exch(a,j,j+1);isSkip = false;}}if (isSkip) {break;}}}/*比较v元素是否大于w元素*/private static boolean greater(Comparable v,Comparable w){return v.compareTo(w)>0;}/*数组元素i和j交换位置*/private static void exch(Comparable[] a,int i,int j){Comparable t = a[i];a[i]=a[j];a[j]=t;}//测试代码public static void main(String[] args) {Integer[] a = {1,2,3};Bubble.sort(a);System.out.println(Arrays.toString(a));}
}