根据指定条件C＃从List中选择随机数

Question

我试图从列表中生成一个唯一的随机数。在这里，用户将输入以下内容：

1. 所需的随机数
2. 编号C1，C2和C3项目。

示例： 10个包含C1-5，C2-4和C3-1的随机数。

因此，根据这些条件，需要生成随机数列表。

我的列表看起来像这样

1   C1
2   C2
3   C3
4   C3
5   C2
6   C1
7   C2
8   C3
9   C1
10  C2
11  C1
12  C3
13  C3
14  C1
15  C2
16  C2
17  C4
18  C3
19  C4
20  C4
21  C4
22  C1
23  C2
24  C3
25  C4
26  C3
27  C4

我的代码如下所示：

protected void BtnGenerate_Click(object sender, EventArgs e)
{
            List<string> labels; // Holds all Labels (unique)
            List<string> values; // Holds all numbers of labels
            Random r = new Random();
            StringBuilder sb=new StringBuilder(100);

            sb.Clear();
            var randoms = values.OrderBy(x => r.Next()).Take(Convert.ToInt16(txtNumberOfRandomNumbers.Text));
            foreach (var item in randoms)
            {
                sb.Append(item.ToString() + ",");
            }

            lblRandomNumbers.Text = sb.ToString().Remove(sb.ToString().LastIndexOf(","));
}

我坚持如何将这些条件添加到随机函数中。请帮帮我。

Answer 1

我建议生成必需的项目，然后改组合并，例如：

// Simplest, but not thread safe
static Random s_Gen = new Random();

private static string Solution(int all, int c1, int c2, int c3) {
  return string.Join(",", new[] {
    Enumerable.Repeat("C1", c1),
    Enumerable.Repeat("C2", c2),
    Enumerable.Repeat("C3", c3),
    Enumerable.Repeat("C4", all - c1 - c2 - c3), }
  .SelectMany(item => item)
  .OrderBy(item => s_Gen.NextDouble()));  
}

protected void BtnGenerate_Click(object sender, EventArgs e) {
  lblRandomNumbers.Text = Solution(27, 10, 5, 3);
}

Answer 2

请尝试以下操作：

List<string> input = new string[] { "C1", "C1", "C1", "C1", "C1", "C1", "C2", "C2", "C2", "C2", "C2", "C2", "C2", "C3", "C3", "C3", "C3", "C3", "C3", "C3", "C3", "C4", "C4", "C4", "C4", "C4", "C4" }.ToList();

Random rand = new Random();

List<string> output = input.Select(x => new { number = x, rand = rand.Next() }).OrderBy(x => x.rand).Select(x => x.number).ToList();