C#生成N个不重复随机数的两个函数

//演示

using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;

namespace 生成N个不重复随机数的两个函数
{
    class Program
    {
        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.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;
        }

    }
}

 

 

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