Java快排、冒泡、選擇最基礎的學習記錄

代碼學習記錄

沒有任何優化，最最基礎的代碼學習。

class Test_Sort
{
    public static void main(String[] args) 
    {
        //快排
        int [] num = {4,9,6,5,0,7,3,8,2,10,5,1};
        quickSort(num, 0 , num.length- 1);
        printNum(num);
        //冒泡
        int [] num_2 = {4,9,6,5,0,7,3,8,2,10,5,1};
        bubbleSort(num_2);
        printNum(num_2);
        //選擇
        int [] num_3 = {4,9,6,5,0,7,3,8,2,10,5,1};
        selectSort(num_3);
        printNum(num_3);
    }
    //快排
    private static void quickSort(int[]num,int l,int r){
        if(l < r){
            int i = l, j = r;
            int temp = num[i];
            while(i < j){
                while(i < j && num[j] >= temp){
                    j --;
                }
                if(i < j){
                    num[i++]=num[j];
                }
                while(i < j && num[i] <= temp){
                    i ++;
                }
                if (i < j)
                {
                    num[j--] = num[i];
                }
            }
            num[i] = temp;
            quickSort(num,l,i-1);
            quickSort(num,i+1,r);
        }
    }

    //冒泡排序
    private static void bubbleSort(int[]num){
       for (int i = 0; i < num.length-1; i ++ )
       {
           for (int j = 0; j < num.length - i - 1 ; j ++)
           {
               exchange(num,j,j+1);//相鄰位置比較交換
           }
       }
    } 

    //選擇排序
    private static void selectSort(int[]num){
        for (int i = 0;i < num.length - 1 ; i ++ )
        {
            for (int j = i+1; j < num.length;j ++ )
            {
                 exchange(num,i,j);
            }
        }
    }

    //交換數字
    private static void exchange(int[]num,int i,int j){
        if( num [i] >= num[j]){
             int temp = num[i];
             num[i] = num[j];
             num[j] = temp;
        }
    }

    //打印
    private static void printNum(int[] num){
        for(int m : num){
            System.out.print(m+", ");
        }
        System.out.println("");
    }
}