Java排序算法：冒泡排序

public interface Sort {
    public boolean sort(int[] arr);
}

package com.lhk.sortDemo;

import java.util.Arrays;

public class BubbleSort implements Sort{

    public boolean sort(int[] arr) {
        if(arr == null){
            return false;
        }

        if(arr.length <= 1){
            return true;
        }
        boolean flag = true;
        int length = arr.length;
        for(int i = 0; i < length - 1 && flag; i++){
            flag = false;
            for(int j = 0; j < length - i - 1; j++){
                if(arr[j] > arr[j + 1]){
                    swap(arr, j , j + 1);
                    flag = true;
                }
            }
            System.out.println(" sort num =" + (i+1) +" :" + Arrays.toString(arr));
        }
        return true;
    }


    private void swap(int[] arr, int start, int end){
        // 安全性判断就不做了。。
        int temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;
    }

}

public class SortDemo1 {

    /**
     * @param args
     */
    public static void main(String[] args) {

        int[] arr = {1,4,6,8,1,11,34,2,67,5,1,9,10,13,2,4,5};

        // 冒泡排序
        Sort sort = new BubbleSort();

        System.out.println("before sort :" + Arrays.toString(arr));

        sort.sort(arr);


        System.out.println("after sort :" + Arrays.toString(arr));
    }

}

结果：
before sort :[1, 4, 6, 8, 1, 11, 34, 2, 67, 5, 1, 9, 10, 13, 2, 4, 5]
 sort num =1 :[1, 4, 6, 1, 8, 11, 2, 34, 5, 1, 9, 10, 13, 2, 4, 5, 67]
 sort num =2 :[1, 4, 1, 6, 8, 2, 11, 5, 1, 9, 10, 13, 2, 4, 5, 34, 67]
 sort num =3 :[1, 1, 4, 6, 2, 8, 5, 1, 9, 10, 11, 2, 4, 5, 13, 34, 67]
 sort num =4 :[1, 1, 4, 2, 6, 5, 1, 8, 9, 10, 2, 4, 5, 11, 13, 34, 67]
 sort num =5 :[1, 1, 2, 4, 5, 1, 6, 8, 9, 2, 4, 5, 10, 11, 13, 34, 67]
 sort num =6 :[1, 1, 2, 4, 1, 5, 6, 8, 2, 4, 5, 9, 10, 11, 13, 34, 67]
 sort num =7 :[1, 1, 2, 1, 4, 5, 6, 2, 4, 5, 8, 9, 10, 11, 13, 34, 67]
 sort num =8 :[1, 1, 1, 2, 4, 5, 2, 4, 5, 6, 8, 9, 10, 11, 13, 34, 67]
 sort num =9 :[1, 1, 1, 2, 4, 2, 4, 5, 5, 6, 8, 9, 10, 11, 13, 34, 67]
 sort num =10 :[1, 1, 1, 2, 2, 4, 4, 5, 5, 6, 8, 9, 10, 11, 13, 34, 67]
 sort num =11 :[1, 1, 1, 2, 2, 4, 4, 5, 5, 6, 8, 9, 10, 11, 13, 34, 67]
after sort :[1, 1, 1, 2, 2, 4, 4, 5, 5, 6, 8, 9, 10, 11, 13, 34, 67]

冒泡排序是一种效率低下的排序方法，在数据规模很小时，可以采用。数据规模比较大时，最好用其它排序方法。