c# - 我将数组向左旋转 N 次的逻辑缺陷在哪里？

Question

我已经从这里开始一个小时了，但无法弄清楚我哪里出错了。我的实现是

static void LeftRotation(int[] arr, int d)
{
    int[] copy = arr.Select(val => val).ToArray();
    for(int i = 0; i < arr.Length; ++i)
    {
        int j = i - d;
        arr[i] = j < 0 ? copy[copy.Length + j] : copy[j];           
    }
}

和d是旋转的次数。

例如arr=[1,2,3,4], d= 2 --> arr=[3,4,1,2]

Answer 1

另一种方式，举个例子:

static void LeftRotation(int[] arr, int d)
{
    for (int i = 1; i <= d; i++)
    {
        //saves the first element
        int temp = arr[0];

        //moves each element to the left, starting from the 2nd
        for (int j = 1; j < arr.Length; ++j)
        {
            arr[j - 1] = arr[j];
        }

        //replaces the last elmt with the previously saved first elmt
        arr[arr.Length - 1] = temp;
    }
}