[ICPC2018 Qingdao R] Function and Function
题意翻译
### 题目描述
如果我们定义 $f(0) = 1$,$f(1) = 0$,$f(4) = 1$,$f(8) = 2$,$f(16) = 1$ …… 你知道函数 $f$ 意味着什么吗?
其实,$f(x)$ 计算的是 $x$ 中每个数字所产生的封闭区域的总数。下表显示了每个数字产生的封闭区域数:
![](https://cdn.luogu.com.cn/upload/image_hosting/sdv14tzu.png)
例如,$f(1234) = 0 + 0 + 0 + 1 = 1$,$f(5678) = 0 + 1 + 0 + 2 = 3$。
现在,我们用以下等式定义递归函数 $g$:
$$\begin{cases} g^0(x) = x \\ g^k(x) = f(g^{k-1}(x)) & \text{if } k \ge 1 \end{cases}$$
例如,$g^2(1234) = f(f(1234)) = f(1) = 0$,$g^2(5678) = f(f(5678)) = f(3) = 0$。
给定两个整数 $x$ 和 $k$,请计算 $g^k(x)$ 的值。
### 输入格式
有多个测试用例。输入的第一行包含一个整数 $T$(大约 $10 ^ 5$),表示测试用例的数量。
之后的每行包含两个整数 $x$ 和 $k$($0 \le x, k \le 10^9$)。正整数不带前导零,零则正好是一个 "0"。
### 输出格式
对每个测试用例输出一行,其中包含一个整数,表示 $g^k(x)$ 的值。
题目描述
If we define $f(0) = 1, f(1) = 0, f(4) = 1, f(8) = 2, f(16) = 1, \dots$, do you know what function $f$ means?
Actually, $f(x)$ calculates the total number of enclosed areas produced by each digit in $x$. The following table shows the number of enclosed areas produced by each digit:
![](https://cdn.luogu.com.cn/upload/image_hosting/sdv14tzu.png)
For example, $f(1234) = 0 + 0 + 0 + 1 = 1$, and $f(5678) = 0 + 1 + 0 + 2 = 3$.
We now define a recursive function $g$ by the following equations:
$$\begin{cases} g^0(x) = x \\ g^k(x) = f(g^{k-1}(x)) & \text{if } k \ge 1 \end{cases}$$
For example, $g^2(1234) = f(f(1234)) = f(1) = 0$, and $g^2(5678) = f(f(5678)) = f(3) = 0$.
Given two integers $x$ and $k$, please calculate the value of $g^k(x)$.
输入输出格式
输入格式
There are multiple test cases. The first line of the input contains an integer $T$ (about $10^5$), indicating the number of test cases. For each test case:
The first and only line contains two integers $x$ and $k$ ($0 \le x, k \le 10^9$). Positive integers are given without leading zeros, and zero is given with exactly one `0'.
输出格式
For each test case output one line containing one integer, indicating the value of $g^k(x)$.
输入输出样例
输入样例 #1
6
123456789 1
888888888 1
888888888 2
888888888 999999999
98640 12345
1000000000 0
输出样例 #1
5
18
2
0
0
1000000000
说明
![](https://cdn.luogu.com.cn/upload/image_hosting/fjjr5xin.png)