Question

我试图在我的快速排序算法中添加一个计数器，以显示在给定阵列上执行的交换总数。但是，我没有运气，并且正在生成明显不正确的值（14）。

被操纵的数组是“#r;＆＃39;这是128个十进制数的集合;

1.960 2.010 2.020 1.940 2.030 2.050 2.000 1.890 1.860 1.960 1.990 2.010 2.010 2.010 1.960 1.940 1.920 1.930 1.980 1.960 1.940 1.900 1.860 1.890 1.860 1.860 1.820 1.810 1.790 1.750 1.780 1.850 1.790 1.790 1.780 1.770 1.760 1.770 1.670 1.610 1.610 1.590 1.540 1.520 1.510 1.540 1.620 1.600 1.560 1.570 1.470 1.420 1.440 1.410 1.450 1.370 1.340 1.320 1.330 1.430 1.440 1.430 1.470 1.480 1.510 1.570 1.630 1.680 1.720 1.710 1.670 1.650 1.620 1.610 1.560 1.580 1.570 1.630 1.640 1.720 1.750 1.750 1.680 1.610 1.620 1.600 1.570 1.510 1.530 1.520 1.550 1.550 1.670 1.650 1.540 1.560 1.710 1.860 1.830 1.670 1.750 1.760 1.780 1.890 2.010 2.010 1.970 1.980 2.040 2.020 2.020 2.020 2.080 2.080 2.080 2.100 2.170 2.160 2.150 2.150 2.120 2.110 2.090 2.130 2.150 2.110 2.100 2.120

这是代码

  int n = arr.Length;
  int step = 0;
  int totalsteps = Quick_Sort(arr, 0, n - 1, step);
  Console.WriteLine("Number of steps = {0}", totalsteps);

 private static int Quick_Sort(decimal[] arr, int left, int right, int step)
    {
        int i, j;
        decimal pivot, temp;
        i = left;
        j = right;
        pivot = arr[(left + right) / 2];
        do
        {
            while ((arr[i] < pivot) && (i < right)) i++;
            while ((pivot < arr[j]) && (j > left)) j--;
            if (i <= j)
            {
                temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
                i++;
                j--;
                step++;
            }
        } while (i <= j);
        if (left < j) Quick_Sort(arr, left, j, step);
        if (i < right) Quick_Sort(arr, i, right, step);
        return step;
    }

已解决：通过引用传递步骤值，现在按预期工作

Answer 1

此

有3种可能的解决方案

返回值

private static int Quick_Sort(decimal[] arr, int left, int right)
{
   int step = 0;
   int i, j;
   decimal pivot, temp;
   i = left;
   j = right;
   pivot = arr[(left + right) / 2];
   do
   {
      while ((arr[i] < pivot) && (i < right)) i++;
      while ((pivot < arr[j]) && (j > left)) j--;
      if (i <= j)
      {
         temp = arr[i];
         arr[i] = arr[j];
         arr[j] = temp;
         i++;
         j--;
         step++;
      }
   } while (i <= j);
   if (left < j) step += Quick_Sort(arr, left, j, step);
   if (i < right) step += Quick_Sort(arr, i, right, step);
   return step;
}

参考值

private static void Quick_Sort(decimal[] arr, int left, int right, ref int step)
{
   int i, j;
   decimal pivot, temp;
   i = left;
   j = right;
   pivot = arr[(left + right) / 2];
   do
   {
      while ((arr[i] < pivot) && (i < right)) i++;
      while ((pivot < arr[j]) && (j > left)) j--;
      if (i <= j)
      {
         temp = arr[i];
         arr[i] = arr[j];
         arr[j] = temp;
         i++;
         j--;
         step++;
      }
   } while (i <= j);
   if (left < j)  Quick_Sort(arr, left, j, ref step);
   if (i < right)  Quick_Sort(arr, i, right, ref step);

}

全局变量

private int _step= 0;

private static void Quick_Sort(decimal[] arr, int left, int right)
{
   int i, j;
   decimal pivot, temp;
   i = left;
   j = right;
   pivot = arr[(left + right) / 2];
   do
   {
      while ((arr[i] < pivot) && (i < right)) i++;
      while ((pivot < arr[j]) && (j > left)) j--;
      if (i <= j)
      {
         temp = arr[i];
         arr[i] = arr[j];
         arr[j] = temp;
         i++;
         j--;
         _step++;
      }
   } while (i <= j);
   if (left < j)  Quick_Sort(arr, left, j );
   if (i < right)  Quick_Sort(arr, i, right);
}

原始回答

您没有将结果从递归

添加回step

if (left < j) step += Quick_Sort(arr, left, j, step);
if (i < right) step += Quick_Sort(arr, i, right, step);

将计数器添加到快速排序算法以显示交换操作的总数

1 个答案: