C#生成100个不重复的随机数算法(转)
C#生成100个不重复的随机数算法,从1~1000中生成不重复的随机数100个,用到了hashtable,这样的话减少检索重复数的范围,这个也是面试时经常问到的一个题目。
代码如下:
Int32 count = 0;
Dictionary<Int32,IList<Int32>> results=new Dictionary<int,IList<int>>();
while (count < 100)
{
while (true)
{
Int32 rand = new Random().Next(1, 1000);
Int32 mod = rand % 10;
if (results.Keys.Contains(mod))
{
if (!results[mod].Contains(rand))
{
results[mod].Add(rand);
count++;
break;
}
}
else
{
IList<Int32> lists = new List<Int32>();
lists.Add(rand);
results.Add(mod, lists);
count++;
break;
}
}
}
//output
foreach (Int32 k in results.Keys)
{
foreach (Int32 v in results[k])
{
Response.Write(v.ToString()+" ");
}
}
Response.Write("<br/>"+count.ToString());
Response.Flush();
Response.End();