编写一个函数，根据给定的概率生成3个数字之一

您将获得一个函数rand(a，b)，该函数将生成[a，b](含)之间的等概率随机数。使用给定的rand(a，b)生成3个具有概率P(x)，P(y)，P(z)的数x，y，z，使得P(x)+ P(y)+ P(z)= 1 )函数。
这个想法是利用提供的rand(a，b)的等概率特征。假设给定的概率为百分比形式，例如P(x)= 40％，P(y)= 25％，P(z)= 35％。 。

以下是详细步骤。
1)生成一个介于1到100之间的随机数。由于它们是等概率的，因此每个数字出现的概率为1/100。
2)以下是有关生成随机数“ r”的一些重要注意事项。
a)’r’小于或等于P(x)，概率为P(x)/ 100。
b)’r’大于P(x)且小于或等于P(x)+ P(y)，且P(y)/ 100。
c)’r’大于P(x)+ P(y)且小于或等于100(或P(x)+ P(y)+ P(z))，概率为P(z)/ 100。

C

// This function generates 'x' with probability px/100, 'y' with
// probability py/100  and 'z' with probability pz/100:
// Assumption: px + py + pz = 100 where px, py and pz lie
// between 0 to 100
int random(int x, int y, int z, int px, int py, int pz)
{      
        // Generate a number from 1 to 100
        int r = rand(1, 100);
      
        // r is smaller than px with probability px/100
        if (r <= px)
            return x;
 
         // r is greater than px and smaller than or equal to px+py
         // with probability py/100
        if (r <= (px+py))
            return y;
 
         // r is greater than px+py and smaller than or equal to 100
         // with probability pz/100
        else
            return z;
}

Python

import random
 
# This function generates 'x' with probability px/100, 'y' with
# probability py/100  and 'z' with probability pz/100:
# Assumption: px + py + pz = 100 where px, py and pz lie
# between 0 to 100
def random(x, y, z, px, py, pz): 
     
    # Generate a number from 1 to 100
    r = random.randint(1, 100)
     
    #  r is smaller than px with probability px/100
    if (r <= px):
        return x
     
    # r is greater than px and smaller than
    # or equal to px+py with probability py/100
    if (r <= (px+py)):
        return y
         
    # r is greater than px+py and smaller than
    # or equal to 100 with probability pz/100
    else:
        return z
     
# This code is contributed by rohan07