Valera and Number
题意翻译
给出一个数 $x$,对它进行 $k$ 次操作,每次操作:
- 以 $p \%$ 的概率对它乘以 $2$。
- 以 $(100 - p) \%$ 的概率对它加上 $1$。
求该数最终二进制下末尾 $0$ 个数的期望。
题目描述
Valera is a coder. Recently he wrote a funny program. The pseudo code for this program is given below:
```plain
//input: integers x, k, p
a = x;
for(step = 1; step <= k; step = step + 1){
rnd = [random integer from 1 to 100];
if(rnd <= p)
a = a * 2;
else
a = a + 1;
}
s = 0;
while(remainder after dividing a by 2 equals 0){
a = a / 2;
s = s + 1;
}
```
Now Valera wonders: given the values $ x $ , $ k $ and $ p $ , what is the expected value of the resulting number $ s $ ?
输入输出格式
输入格式
The first line of the input contains three integers $ x,k,p $ ( $ 1<=x<=10^{9}; 1<=k<=200; 0<=p<=100 $ ).
输出格式
Print the required expected value. Your answer will be considered correct if the absolute or relative error doesn't exceed $ 10^{-6} $ .
输入输出样例
输入样例 #1
1 1 50
输出样例 #1
1.0000000000000
输入样例 #2
5 3 0
输出样例 #2
3.0000000000000
输入样例 #3
5 3 25
输出样例 #3
1.9218750000000
说明
If the concept of expected value is new to you, you can read about it by the link:
http://en.wikipedia.org/wiki/Expected\_value