《OD学算法》排序之冒泡排序

冒泡排序

一语中的：丢一把沙子，轻的物体往上浮。

基本思想：通过无序区中相邻记录关键字间的比较和位置的交换,使关键字最小的记录如气泡一般逐渐往上“漂浮”直至“水面”。 

代码示例：

import java.util.Arrays;

public class BubbleSort {

    public int[] bubbleSort(int[] array) {
        int length = array.length;
        boolean swapped = true;
        int compareCount = 0;
        do {
            swapped = false;
            for (int i = 0; i < length - 1; i++) {
                System.out.println("compare(" + array[i] + "," + array[i + 1] + ")");
                if (array[i] > array[i + 1]) {
                    int temp = array[i];
                    array[i] = array[i + 1];
                    array[i + 1] = temp;
                    swapped = true;
                }
                compareCount++;
                System.out.println("第" + i + "趟 array=" + Arrays.toString(array));
            }
        } while (swapped);
        System.out.println("冒泡排序比较次数=" + compareCount);
        return array;
    }
    
    public int[] bubbleSort2(int[] array) {
        int length = array.length;
        int compareCount = 0;
        for(int j = 0; j < length - 1; j++){
            for(int i = 0; i < length - j - 1; i++){
                System.out.println("compare(" + array[i] + "," + array[i + 1] + ")");
                if(array[i] > array[i + 1]){
                    int temp = array[i];
                    array[i] = array[i + 1];
                    array[i + 1] = temp;
                }
                compareCount++;
            }
            System.out.println("第" + j + "趟 array=" + Arrays.toString(array));
        }
        System.out.println("冒泡排序比较次数=" + compareCount);
        return array;
    }

}