C#实现几种排序算法

以下是C#实现的几种常见排序算法示例：

1. 冒泡排序

static void BubbleSort(int[] arr)
{
    int len = arr.Length;
    for (int i = 0; i < len - 1; i++)
    {
        for (int j = 0; j < len - i - 1; j++)
        {
            if (arr[j] > arr[j + 1])
            {
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

2. 选择排序

static void SelectionSort(int[] arr)
{
    int len = arr.Length;
    for (int i = 0; i < len - 1; i++)
    {
        int minIndex = i;
        for (int j = i + 1; j < len; j++)
        {
            if (arr[j] < arr[minIndex])
            {
                minIndex = j;
            }
        }
        if (minIndex != i)
        {
            int temp = arr[i];
            arr[i] = arr[minIndex];
            arr[minIndex] = temp;
        }
    }
}

3. 插入排序

static void InsertionSort(int[] arr)
{
    int len = arr.Length;
    for (int i = 1; i < len; i++)
    {
        int temp = arr[i];
        int j = i - 1;
        while (j >= 0 && arr[j] > temp)
        {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = temp;
    }
}

4. 快速排序

static void QuickSort(int[] arr, int left, int right)
{
    if (left < right)
    {
        int pivot = Partition(arr, left, right);
        QuickSort(arr, left, pivot - 1);
        QuickSort(arr, pivot + 1, right);
    }
}

static int Partition(int[] arr, int left, int right)
{
    int pivot = arr[right];
    int i = left - 1;
    for (int j = left; j < right; j++)
    {
        if (arr[j] < pivot)
        {
            i++;
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }
    int temp2 = arr[i + 1];
    arr[i + 1] = arr[right];
    arr[right] = temp2;
    return i + 1;
}

5. 归并排序

static void MergeSort(int[] arr, int left, int right)
{
    if (left < right)
    {
        int mid = (left + right) / 2;
        MergeSort(arr, left, mid);
        MergeSort(arr, mid + 1, right);
        Merge(arr, left, mid, right);
    }
}

static void Merge(int[] arr, int left, int mid, int right)
{
    int[] temp = new int[right - left + 1];
    int i = left;
    int j = mid + 1;
    int k = 0;

    while (i <= mid && j <= right)
    {
        if (arr[i] < arr[j])
        {
            temp[k++] = arr[i++];
        }
        else
        {
            temp[k++] = arr[j++];
        }
    }

    while (i <= mid)
    {
        temp[k++] = arr[i++];
    }

    while (j <= right)
    {
        temp[k++] = arr[j++];
    }

    for (int m = 0; m < temp.Length; m++)
    {
        arr[left + m] = temp[m];
    }
}