Java Bubble排序示例

冒泡排序是最简单的排序算法，它比较前两个元素，如果第一个大于第二个元素，则将它们交换，然后继续进行（比较和交换）下一对相邻元素。 然后，它再次从前两个元素开始，进行比较，交换，直到不再需要交换为止。

1.解释

#unsorted data -> [99, 88, 55, 77, 1, 66]

#1 iteration.
#1.1 -> [ 99 , 88 , 55, 77, 1, 66] -> [ 88 , 99 , 55, 77, 1, 66]
#1.2 -> [88, 99 , 55 , 77, 1, 66] -> [88, 55 , 99 , 77, 1, 66]
#1.3 -> [88, 55, 99 , 77 , 1, 66] -> [88, 55, 77 , 99 , 1, 66]
#1.4 -> [88, 55, 77, 99 , 1 , 66] -> [88, 55, 77, 1 , 99 , 66]
#1.5 -> [88, 55, 77, 1, 99 , 66 ] -> [88, 55, 77, 1, 66 , 99 ]

#2 iteration.
#2.1 -> [ 88 , 55 , 77, 1, 66, 99] -> [ 55 , 88 , 77, 1, 66, 99]
#2.2 -> [55, 88 , 77 , 1, 66, 99] -> [55, 77 , 88 , 1, 66, 99]
#2.3 -> [55, 77, 88 , 1 , 66, 99] -> [55, 77, 1 , 88 , 66, 99]
#2.4 -> [55, 77, 1, 88 , 66 , 99] -> [55, 77, 1, 66 , 88 , 99]

#3 iteration.
#3.1 -> [ 55 , 77 , 1, 66, 88, 99] -> [55, 77, 1, 66, 88, 99] {no swap}
#3.2 -> [55, 77 , 1 , 66, 88, 99] -> [55, 1 , 77 , 66, 88, 99]
#3.3 -> [55, 1, 77 , 66 , 88, 99] -> [55, 1, 66 , 77 , 88, 99]

#4 iteration.
#4.1 -> [ 55 , 1 , 66, 77, 88, 99] -> [ 1 , 55 , 66, 77, 88, 99]
#4.2 -> [ 1 , 55 , 66, 77, 88, 99] -> [1, 55, 66, 77, 88, 99] {no swap}

#5 iteration.
#5.1 -> [ 1 , 55 , 66, 77, 88, 99] -> is_sorted = true, break;

这是Java气泡排序实现。

public static void sort(int[] input) {

        int inputLength = input.length;
        int temp;
        boolean is_sorted;

        for (int i = 0; i < inputLength; i++) {

            is_sorted = true;

            for (int j = 1; j < (inputLength - i); j++) {

                if (input[j - 1] > input[j]) {
                    temp = input[j - 1];
                    input[j - 1] = input[j];
                    input[j] = temp;
                    is_sorted = false;
                }

            }

            // is sorted? then break it, avoid useless loop.
            if (is_sorted) break;

            System.out.println("\n");
            
        }
        
    }

2. Java Bubble排序示例

一个完整的示例演示了如何使用冒泡排序算法对简单数据集进行排序，支持升序或降序。

BubbleSortExample.java

package com.mkyong;

import java.util.Arrays;
import java.util.stream.Collectors;

public class BubbleSortExample{

    public static void main(String[] args) {

        int[] array = {99, 88, 55, 77, 1, 66};

        System.out.print("unsorted data: ");
        printArray(array);

        System.out.print("ascending order: "); //1,55,66,77,88,99
        bubble_sort(array);

        printArray(array);

        System.out.print("descending order: "); //99,88,77,66,55,1
        bubble_sort(array, false);

        printArray(array);

    }

    private static void bubble_sort(int[] input) {
        bubble_sort(input, true);
    }

    private static void bubble_sort(int[] input, boolean ascending) {

        int inputLength = input.length;
        int temp;
        boolean is_sorted;

        for (int i = 0; i < inputLength; i++) {

            is_sorted = true;

            for (int j = 1; j < (inputLength - i); j++) {

                if (ascending) {
                    if (input[j - 1] > input[j]) {
                        temp = input[j - 1];
                        input[j - 1] = input[j];
                        input[j] = temp;
                        is_sorted = false;
                    }
                } else {
                    if (input[j - 1] < input[j]) {
                        temp = input[j - 1];
                        input[j - 1] = input[j];
                        input[j] = temp;
                        is_sorted = false;
                    }

                }

            }

            // is sorted? then break it, avoid useless loop.
            if (is_sorted) break;

        }

    }

    private static void printArray(int[] data) {
        String result = Arrays.stream(data)
                .mapToObj(String::valueOf)
                .collect(Collectors.joining(","));
        System.out.println(result);
    }

}

输出量

unsorted data: 99,88,55,77,1,66
ascending order: 1,55,66,77,88,99
descending order: 99,88,77,66,55,1

参考文献

1. 不同种类的排序
2. 维基百科排序算法

标签： 算法 气泡排序 排序

翻译自: https://mkyong.com/java/java-bubble-sort-example/