LOTT - Xổ số
Tác giả: flashmt
Ngôn ngữ: C++
#include<iostream>
#include<string>
using namespace std;
long long c(int x,int y)
{
if (x>y) return 0;
if (x==0) return 1;
return c(x-1,y)*(y-x+1)/x;
}
int main()
{
string s;
int n;
double x,y;
while (1)
{
cin >> s;
if (s=="[END]") return 0;
if (s=="[CASE]")
{
cin >> n;
x=c(5,n)*3125+c(3,n-1)*1250*n+c(2,n-1)*500*n;
y=c(5,5*n);
cout << 1-x/y << endl;
}
}
return 0;
}