简单排序

一冒泡排序

二选择排序

三插入排序

下面我们分步讲一下这三种排序。首先来看一下冒泡排序。

package ch02;

public class BubbleSort {

    public static void sort(long [] arr){
        long temp = 0;
        for (int i = 0;i<arr.length-1;i++) {//i表示第几趟排序
            for (int j = arr.length-1;j>i;j--) {
                if (arr[j] <arr[j-1]) {
                    //交换
                    temp = arr[j];
                    arr[j] = arr[j-1];
                    arr[j-1] = temp;
                }
            }
        }
    }
    
    public static void main(String[] args) {
        long[]arr = new long[5];
        arr[0] = 34;
        arr[1] = 23;
        arr[2] = 1;
        arr[3] = 2;
        sort(arr);
        for (int i = 0;i<arr.length;i++) {
            System.out.print(arr[i]+" ");
        }
        
    }
    
}

2：选择排序：代码实现

package ch02;

public class SelectionSort {

    public static void sort(long [] arr){
        int k = 0;
        long temp = 0;
        for (int i = 0;i<arr.length;i++) {//趟数
            k = i;
            for (int j = i;j<arr.length;j++) {
                if (arr[j] < arr[k]) {//选择最小的交换
                    k = j;
                }
            }
//交换
            temp = arr[i];
            arr[i] = arr[k];
            arr[k] = temp;
        }
    }
    public static void main(String[] args) {
        long[]arr = new long[5];
        arr[0] = 34;
        arr[1] = 23;
        arr[2] = 1;
        arr[3] = 2;
        sort(arr);
        for (int i = 0;i<arr.length;i++) {
            System.out.print(arr[i]+" ");
        }
    }
}

3，插入排序：代码实现（代码有问题）

package ch02;

public class InsertSort {

    public static void sort(long [] arr){
        long temp = 0;
        for (int i = 1;i<arr.length;i++) {
            temp = arr[i];
            int j = i;
            while (j > 0 && arr[j] >= temp) {
                arr[j] = arr[j-1];
                j--;
            }
            arr[j] = temp;
        }
    }
    public static void main(String[] args) {
        long[]arr = new long[5];
        arr[0] = 34;
        arr[1] = 23;
        arr[2] = 1;
        arr[3] = 2;
        arr[4] = 0;
        sort(arr);
        for (int i = 0;i<arr.length;i++) {
            System.out.print(arr[i]+" ");
        }
    }
}