using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
// 一个BOSS掉4个装备，每杀死次BOSS都只掉1个，
// 4个装备掉的几率相等，问同一玩家要凑齐4个装备平均要杀多少次BOSS？

namespace Boss
{
class Program
{
static Random rd = new Random();
static bool test( int [] a)
{
for ( int i = 0 ; i < a.Length; i ++ )
{
if (a[i] != 1 )
return true ;
}
return false ;
}
static int sim()
{
int [] a = { 0 , 0 , 0 , 0 };
int i = 0 ;
while (test(a))
{
a[rd.Next( 0 , 4 )] = 1 ;
i ++ ;
}
return i;
}
static void boss1()
{
double sum = 0 , summ = 0 ;
int COUNT = 1000000 ;
for ( int j = 0 ; j < 10 ; j ++ )
{
for ( int i = 0 ; i < COUNT; i ++ )
{
sum += sim();
}
sum /= COUNT;
summ += sum;
}
Console.WriteLine( " 平均结果是:{0}; " , summ / 10 );
}

static void boss3()
{
double s1 = 27.0 / 64 , s2 = 3.0 / 8 , s3 = 3.0 / 64 ;
double tmp = 4 * (s1 - s2 + s3),s = 0 ;
for ( int i = 5 ;tmp > 0.00001 ;i ++ )
{
s += tmp;
s1 = s1 * 3 / 4 ;
s2 = s2 / 2 ;
s3 = s3 / 4 ;
tmp = i * (s1 - s2 + s3);
}
Console.WriteLine( " 计算和:{0} " , s);
}
static void Main( string [] args)
{
Console.WriteLine( " 模拟输出： " );
boss1();
Console.WriteLine( " 计算输出： " );
boss3();
}
}
}