归并算法的C＃ [英] MergeSort algorithm in c#

问题描述

我写了下面$ C $下合并类：

I wrote below code for Merge Class :

class Merge
{

    public static void sort(IComparable[] a)
    {
        sort(a, 0, a.Length);
    }

    public static void sort(IComparable[] a, int low, int high)
    {
        int N = high - low;
        if (N <= 1)
            return;

        int mid = low + N / 2;

        sort(a, low, mid);
        sort(a, mid, high);

        IComparable[] aux = new IComparable[N];
        int i = low, j = mid;
        for (int k = 0; k < N; k++)
        {
            if (i == mid) aux[k] = a[j++];
            else if (j == high) aux[k] = a[i++];
            else if (a[j].CompareTo(a[i]) < 0) aux[k] = a[j++];
            else aux[k] = a[i++];
        }

        for (int k = 0; k < N; k++)
        {
            a[low + k] = aux[k];
        }
    }

    private static Boolean isSorted(IComparable[] a)
    {
        for (int i = 1; i < a.Length; i++)
            if (a[i].CompareTo(a[i - 1]) < 0) return false;
        return true;
    }

}

和低于code是实现。我认为以下code should't是错误的！但它的简化版，编译...

And below code is Implementation. i thought below code should't be wrong! but it's does't compile...

class Program
{
    static void Main(string[] args)
    {
    Merge ms = new Merge();

    Double[] MyArray = { 80,10,52,7,36,7,67,1,8,54 };
    Console.WriteLine("first array is: \n");
    for (int k = 0; k < MyArray.Length; k++)
    {
        Console.Write(MyArray[k]);
        if (k<9)
           Console.Write(" , ");
    }
    ms.sort(MyArray);  // Error is here. Does't compile !!!
    Console.WriteLine("\n");
    Console.WriteLine("\nsorted array is: \n ");
    for (int k = 0; k < MyArray.Length; k++)
    {
        Console.Write(MyArray[k]);
        if (k<9)
           Console.Write(" , ");
    }
    Console.ReadLine();
    }
}

这是简化版，编译。错误是在 ms.sort（MYARRAY）; 。 我究竟做错了什么？ 请带我......

It's does't compile. Error is in ms.sort(MyArray);. What am i doing wrong? Please lead me...

问候

推荐答案

有两个问题code：

1. 签名不符， IComparable的[] 与不直接兼容双[] 在这种情况下，
2. 您不能调用排序直接通过实例方法

1. The signature doesn't match, IComparable[] is not directly compatible with double[] in this case
2. You cannot call the sort method through the instance directly

变化的最小量来解决，这将是使通用的方法，并调用 Merge.sort 而不是 ms.sort 。

The minimal amount of changes to fix this would be to make the method generic, and call Merge.sort instead of ms.sort.

下面是我会怎么实施排序：

public static void sort<T>(T[] a)
    where T : IComparable<T>
{
    sort(a, 0, a.Length);
}

public static void sort<T>(T[] a, int low, int high)
    where T : IComparable<T>
{
    int N = high - low;
    if (N <= 1)
        return;

    int mid = low + N / 2;

    sort(a, low, mid);
    sort(a, mid, high);

    T[] aux = new T[N];
    int i = low, j = mid;
    for (int k = 0; k < N; k++)
    {
        if (i == mid) aux[k] = a[j++];
        else if (j == high) aux[k] = a[i++];
        else if (a[j].CompareTo(a[i]) < 0) aux[k] = a[j++];
        else aux[k] = a[i++];
    }

    for (int k = 0; k < N; k++)
    {
        a[low + k] = aux[k];
    }
}

请注意，我改变使用 T 而不是 IComparable的，并增加了一个约束说我们需要一个 T 实现 IComparable的＆LT; T＆GT;

Note that I changed to using T instead of IComparable, and added a constraint saying we need a T that implements IComparable<T>.

此外，从这种变化中您的来电：

Additionally, change your call from this:

ms.sort(...);

这样：

Merge.sort(...);

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