These days, I was working on a lottery software for the company's annual meeting. When I started working on it, I thought the algorithm was very simple. I put the employee's data into the list, and used the list's label as the random number to be obtained. Based on the random number obtained, I decided who won the prize. Later tests found that the distribution of random numbers was very uneven. Later I learned that the random numbers obtained by computers are pseudo-random numbers. When the lottery speed is very fast, the random numbers obtained are very uneven, so a delay must be added in each lottery. Later, the algorithm was redesigned and finally implemented.
The principle of the algorithm is a bit similar to the process of binary search. The probability of drawing the front and back of a coin is the same. When the number of sampling increases infinitely, the probability of drawing is 50%.
The code is as follows:
public partial class MainWindow : Window
{
string s;
int number;
public MainWindow()
{
InitializeComponent();
}
public int getRandom()
{
//string[] arr = new string[5] { "we", "yes", "one", "team" };
Random r = new Random();
int num = 2;
int choose = (num);
return choose;
//(arr[choose].ToString());
}
public string GRandom(int n)
{
//if()
if (n == 0)
{
//s = getRandom() + s;
//(1);
return s;
}
if (n % 2 == 0)
{
n = n / 2;
}
else
{
n = (n - 1) / 2;
//s = getRandom() + s;
}
s = getRandom() + s;
(20);
GRandom(n);
//(1);
return s;
}
public Int32 Estimate(int n)
{
string num = GRandom(n);
number = Convert.ToInt32(num, 2);
if (number > n - 1)
{
//num = "";
s = "";
Estimate(n);
}
//else
return number;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
for (int i = 0; i < 100; i++)
{
+= Estimate(200) + ";";
s = "";
}
}
}
The above algorithm is not very good. Cancel the delay and set the random object as a global variable. The modified version code is as follows:
string s;
int number;
Random r = new Random();
public int getRandom()
{
//string[] arr = new string[5] { "we", "yes", "one", "team" };
//Random r = new Random();
int num = 2;
int choose = (num);
return choose;
//(arr[choose].ToString());
}
public string GRandom(int n)
{
//if()
if (n == 0)
{
//s = getRandom() + s;
//(1);
return s;
}
if (n % 2 == 0)
{
n = n / 2;
}
else
{
n = (n - 1) / 2;
//s = getRandom() + s;
}
s = getRandom() + s;
GRandom(n);
return s;
}
public Int32 Estimate(int n)
{
string num = GRandom(n);
number = Convert.ToInt32(num, 2);
if (number > n - 1)
{
//num = "";
s = "";
Estimate(n);
}
//else
return number;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
for (int i = 0; i < 1000; i++)
{
= Estimate(200);
s = "";
}
//The following is the test
//int a = 0, b = 0, c = 0, d = 0, f = 0;
//for (int i = 0; i < 1000; i++)
//{
// // = Estimate(2);
// int content = Estimate(5);
// s = "";
// switch (content)
// {
// case 0:
// a ++;
// break;
// case 1:
// b ++;
// break;
// case 2:
// c ++;
// break;
// case 3:
// d ++;
// break;
// case 4:
// f ++;
// break;
// }
// = a;
// = b;
// = c;
// = d;
// = f;
//}
}
}
}