c# 概率算法

Question

问个算法问题：有三个字母A,B,C 想通过设置三个概率值比如：0.5,0.2,0.3(相加概率为1)，概率的产生100次ABC三个字母，求思路！！！

Answer 1

先生成50个A、20个B、30个C，随机抽取...

Answer 2

产生这些比率的最小公倍数即可。10000还是几千无所谓。另外还可以直接产生0~1的随机数。
在[0 - a)为A，[a - a+b)为B，[a+b - 1)为C。

Answer 3

真正的概率，即使你连续99次抽到了A，第一百次取到A的概率仍是0.5.楼主首先要清楚，你是要真正按概率取，还是希望取到50个A、20个B、30个C？
这是两道不同的题。

Answer 4

就像8楼所说的，随即一个0-9之间的数，小于5就是a，小于7就是b，剩下是C

Answer 5

取随即数，取值为0-9的数。小于等于5就是A，大于5且小于等于7就是B，大于7且小于等于9为C。

Answer 6

using System;
using System.Collections.Generic;
using System.Text;namespace RandomGenerator
{
    class Program
    {
        const int LEN = 100;
        const int SIZE = 1000;
        const double probA = 0.5;
        const double probB = 0.2;                static void Main(string[] args)
        {
            char[] numberList = new char[LEN];
            Random Rand = new Random((int)DateTime.Now.Ticks);            int num;
            int aThres = (int)(probA * SIZE);
            int bThres = (int)((probA + probB) * SIZE);            // generate the list
            for (int i = 0; i < LEN; i++)
            {
                num = Rand.Next(1, SIZE);                if (num <= aThres)
                {
                    numberList[i] = 'A';
                }
                else if (num <= bThres)
                {
                    numberList[i] = 'B';
                }
                else
                {
                    numberList[i] = 'C';
                }
                Console.Write("{0}\t", numberList[i]);
            }
            Console.WriteLine();            // check result
            int aNum = 0, bNum = 0, cNum = 0;
            for (int i = 0; i < LEN; i++)
            {
                if(numberList[i] == 'A')
                {
                    aNum++;
                }
                else if (numberList[i] == 'B')
                {
                    bNum++;
                }
                else
                {
                    cNum++;
                }
            }
            Console.WriteLine("A: {0}, B: {1}, C: {2}", aNum, bNum, cNum);
        }
    }
}

Answer 7

Random ran = new Random();
            double a = 0.5;
            double b = 0.2;
            double c = 0.3;
            int aIndex = 0;
            int bIndex = 0;
            int cIndex = 0;
            for (int i = 0; i < 100; i++)
            {
                double next = ran.NextDouble();
                if (next <= a)
                {
                    aIndex++;
                }
                else if (a < next && next <= a + b)
                {
                    bIndex++;
                }
                else
                {
                    cIndex++;
                }
            }
            MessageBox.Show(string.Format("A出现{0}次，B出现{1}次，C出现{2}次。",aIndex,bIndex,cIndex));

Answer 8

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;namespace Example
{
    class Program
    {
        static void Main(string[] args)
        {
            char[] ch={'A','B','C'};
            int item;
            int[] count=new int[3]{0,0,0};
            Random random = new Random(Guid.NewGuid().GetHashCode());
            for (int i = 0; i < 100;i++ )
            {
                int r=random.Next(1, 11);
                if ( r<= 5)
                {
                    item = 0;
                    count[item]++;
                    Console.Write(ch[item]);
                }
                else if (r<=7)
                {
                    item = 1;
                    count[item]++;
                    Console.Write(ch[item]);
                }
                else
                {
                    item = 2;
                    count[item]++;
                    Console.Write(ch[item]);
                }
            }            Console.WriteLine("A出现的次数{0}，B出现的次数{1}，C出现的次数{2}", count[0], count[1], count[2]);
            Console.ReadLine();
        }
    }
}