排序算法（冒泡、选择、插入）

------冒泡排序

 

private static void MaoPaoSort()
    {
        int[] array = new int[5] { 4, 5, 10, 6, 7 };
        for (int i = 0; i < array.Length - 1; i++)
        {
            for (int j = array.Length - 1; j > i; j--)
            {
                if (array[j] < array[j - 1])
                {
                    int temp = array[j];
                    array[j] = array[j - 1];
                    array[j - 1] = temp;
                }
            }
        }
        for (int i = 0; i < array.Length; i++)
        {
            Console.WriteLine(array[i]);
        }
    }

---------选择排序

 

 

 private static void SortNum()
    {
        int[] array = new int[5] { 4, 5, 10, 6, 7 };
        for (int i = 0; i < array.Length; i++)
        {
            for (int j = i + 1; j < array.Length; j++)
            {
                if (array[i] > array[j])
                {
                    int temp = array[i];
                    array[i] = array[j];
                    array[j] = temp;
                }
            }
        }
        for (int i = 0; i < array.Length; i++)
        {
            Console.WriteLine(array[i]);
        }
    }

 

 

 

---------选择排序（优化后）

 

  private static void SortNum()
    {
        int[] array = new int[5] { 4, 5, 10, 6, 7 };
        for (int i = 0; i < array.Length - 1; i++)
        {
            //寻找最小数值的下标与第一位交换
            int minIndex = i;
            for (int j = i + 1; j < array.Length; j++)
            {
                if (array[minIndex] > array[j])
                {
                    minIndex = j;
                }
            }
            if (minIndex != i)
            {
                int temp = array[minIndex];
                array[minIndex] = array[i];
                array[i] = temp;
            }
        }
        foreach (var item in array)
        {
            Console.WriteLine(item);
        }
    }

--------插入排序

 

 

  private static void InsertSortNum()
    {
        int[] unsorted = new int[5] { 5, 2, 4, 6, 1 };

        for (int i = 0; i < unsorted.Length; i++)
        {
            //存储当前unsorted[i]的值
            int temp = unsorted[i];
            //存储当前值的下标
            int j = i;
            //判断当前值与其前一位的大小
            while (j > 0 && unsorted[j - 1] > temp)
            {
                //如果前一位值大于当前值，与unsorted[j] = temp 构成交换值的操作
                unsorted[j] = unsorted[j - 1];
                j--;
            }
            //这个unsorted[j] 相当于unsorted[j-1]
            unsorted[j] = temp;
        }
        for (int i = 0; i < unsorted.Length; i++)
        {
            Console.WriteLine(unsorted[i]);
        }
    }

--------快排

private void QuickSort(int[] arr, int low, int high)
    {
        if (low < high)
        {
            int index = CacluateSort(arr, low, high);
            QuickSort(arr, low, index - 1);
            QuickSort(arr, index + 1, high);
        }
    }

    private int CacluateSort(int[] arr,int low,int high)
    {
        int basePoivt = arr[low];
        while(low<high)
        {
            while (low < high && arr[high] >= basePoivt)
            {
                high--;
            }
            arr[low] = arr[high];
            while (low < high && arr[low] <= basePoivt)
            {
                low++;
            }
            arr[high] = arr[low];
        }
        arr[low] = basePoivt;
        return low;
    }