83 lines
3.2 KiB
Java
83 lines
3.2 KiB
Java
/*
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* The MIT License (MIT)
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*
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* Copyright © 2020 xrv <xrg@live.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package io.github.ehlxr.sort;
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import java.util.Arrays;
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/**
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* 冒泡排序
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* <p>
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* 从无序序列头部开始，进行两两比较，根据大小交换位置，直到最后将最大（小）的数据元素交换到了无序队列的队尾，从而成为有序序列的一部分；
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* 下一次继续这个过程，直到所有数据元素都排好序。
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* <p>
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* 算法的核心在于每次通过两两比较交换位置，选出剩余无序序列里最大（小）的数据元素放到队尾。
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* 时间复杂度：O(n²)
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*
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* @author ehlxr
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* @since 2020-10-01 16:40.
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*/
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public class BubbleSort {
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/**
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* 冒泡排序算法的算法过程如下：
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* ①. 比较相邻的元素。如果第一个比第二个大，就交换他们两个。
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* ②. 对每一对相邻元素作同样的工作，从开始第一对到结尾的最后一对，最后的元素会是最大的数。
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* ③. 针对所有的元素重复以上的步骤，除了最后一个。
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* ④. 持续每次对越来越少的元素重复上面的步骤①~③，直到没有任何一对数字需要比较。
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*/
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public static void sort(int[] arr) {
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//外层：需要 length-1 次循环比较
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for (int i = 0; i < arr.length - 1; i++) {
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boolean flag = false;
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//内层：每次循环需要两两比较的次数，每次比较后，都会将当前最大的数放到最后位置，所以每次比较次数递减一次
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for (int j = 0; j < arr.length - 1 - i; j++) {
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if (arr[j] > arr[j + 1]) {
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flag = true;
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swap(arr, j, j + 1);
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}
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}
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System.out.println("Sorting: " + Arrays.toString(arr));
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if (!flag) {
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break;
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}
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}
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}
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public static void swap(int[] arr, int i, int j) {
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// arr[i] = arr[i] + arr[j];
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// arr[j] = arr[i] - arr[j];
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// arr[i] = arr[i] - arr[j];
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int tmp = arr[i];
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arr[i] = arr[j];
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arr[j] = tmp;
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}
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public static void main(String[] args) {
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sort(new int[]{4, 9, 1, 6, 8, 10});
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}
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}
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