在指定范围内取出n个不重复随机数
Codeusing System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace BerkeleyDBDemo
{
class Class16
{
static void Main(string[] args)
{
DateTime d1 = System.DateTime.Now;
int[] list1 = GetRandom1(1, 100000, 5000);
TimeSpan dd1 = System.DateTime.Now - d1;
DateTime d2 = System.DateTime.Now;
int[] list2 = GetRandom2(1, 100000*100, 5000);
TimeSpan dd2 = System.DateTime.Now - d2;
//foreach (int i in list1)
// Console.Write("{0},", i);
//foreach (int ii in list2)
// Console.Write("{0},", ii);
Console.WriteLine("第一种方法，1-100000 里取5000个用时：{0}", dd1.TotalMilliseconds);
Console.WriteLine("第二种方法，1-100000*100里取5000个用时：{0}", dd2.TotalMilliseconds);
Console.WriteLine("判断第二种方法里是否有重复数，如果是5000就是没有重复的：{0}",RemoveDup(list2).Length);
Console.WriteLine("my test=================");
int[] a=GetRandom1(1, 100, 99);
Array.Sort(a);
foreach(var i in a)
Console.WriteLine(i);
Console.ReadKey();
}
public static int[] RemoveDup(int[] myData)
{
if (myData.Length > 0)
{
Array.Sort(myData);
int size = 1;
for (int i = 1; i < myData.Length; i++)
if (myData[i] != myData[i - 1])
size++;
int[] myTempData = new int[size];
int j = 0;
myTempData[j++] = myData[0];
for (int i = 1; i < myData.Length; i++)
if (myData[i] != myData[i - 1])
myTempData[j++] = myData[i];
return myTempData;
}
return myData;
}
//方法1
public static int[] GetRandom1(int minValue, int maxValue, int count)
{
Random rnd = new Random();
int length = maxValue - minValue + 1;
byte[] keys = new byte[length];
rnd.NextBytes(keys);
int[] items = new int[length];
for (int i = 0; i < length; i++)
{
items[i] = i + minValue;
}
Array.Sort(keys, items);
int[] result = new int[count];
Array.Copy(items, result, count);
return result;
}
//方法2
public static int[] GetRandom2(int minValue, int maxValue, int count)
{
int[] intList = new int[maxValue];
for (int i = 0; i < maxValue; i++)
{
intList[i] = i + minValue;
}
int[] intRet = new int[count];
int n = maxValue;
Random rand = new Random();
for (int i = 0; i < count; i++)
{
int index = rand.Next(0, n);
intRet[i] = intList[index];
intList[index] = intList[--n];
}
return intRet;
}
}
}
