Addition Robot
题意翻译
给出一个长度为 $N$,只含有大写字母 A 和 B 的字符串 $S=S_1S_2S_3...S_n$,定义如下函数 $f(L,R,A,B)$:
```
function f(L, R, A, B):
FOR i from L to R
if S[i] = 'A'
A = A + B
else
B = A + B
return (A, B)
```
给出初始字符串 $S$,你需要执行以下 $Q$ 次操作:
`1 L R`:将 $S_L,S_{L+1},...,S_{R-1},S_r$ 取反(A 变为 B,B 变为 A)。
`2 L R A B`:输出函数调用 $F(L,R,A,B)$ 的结果,对 $10^9+7$ 取模。
$1\le N,Q\le 10^5$
题目描述
Adding two numbers several times is a time-consuming task, so you want to build a robot. The robot should have a string $ S = S_1 S_2 \dots S_N $ of $ N $ characters on its memory that represents addition instructions. Each character of the string, $ S_i $ , is either 'A' or 'B'.
You want to be able to give $ Q $ commands to the robot, each command is either of the following types:
- 1 $ L $ $ R $ . The robot should toggle all the characters of $ S_i $ where $ L \le i \le R $ . Toggling a character means changing it to 'A' if it was previously 'B', or changing it to 'B' if it was previously 'A'.
- 2 $ L $ $ R $ $ A $ $ B $ . The robot should call $ f(L, R, A, B) $ and return two integers as defined in the following pseudocode: ```
<pre class="lstlisting">```
function f(L, R, A, B):<br></br> FOR i from L to R<br></br> if S[i] = 'A'<br></br> A = A + B<br></br> else<br></br> B = A + B<br></br> return (A, B)<br></br>
```
```
You want to implement the robot's expected behavior.
输入输出格式
输入格式
Input begins with a line containing two integers: $ N $ $ Q $ ( $ 1 \le N, Q \le 100\,000 $ ) representing the number of characters in the robot's memory and the number of commands, respectively. The next line contains a string $ S $ containing $ N $ characters (each either 'A' or 'B') representing the initial string in the robot's memory. The next $ Q $ lines each contains a command of the following types.
- 1 $ L $ $ R $ ( $ 1 \le L \le R \le N $ )
- 2 $ L $ $ R $ $ A $ $ B $ ( $ 1 \le L \le R \le N $ ; $ 0 \le A, B \le 10^9 $ )
There is at least one command of the second type.
输出格式
For each command of the second type in the same order as input, output in a line two integers (separated by a single space), the value of $ A $ and $ B $ returned by $ f(L, R, A, B) $ , respectively. As this output can be large, you need to modulo the output by $ 1\,000\,000\,007 $ .
输入输出样例
输入样例 #1
5 3
ABAAA
2 1 5 1 1
1 3 5
2 2 5 0 1000000000
输出样例 #1
11 3
0 1000000000
说明
Explanation for the sample input/output #1
For the first command, calling $ f(L, R, A, B) $ causes the following:
- Initially, $ A = 1 $ and $ B = 1 $ .
- At the end of $ i = 1 $ , $ A = 2 $ and $ B = 1 $ .
- At the end of $ i = 2 $ , $ A = 2 $ and $ B = 3 $ .
- At the end of $ i = 3 $ , $ A = 5 $ and $ B = 3 $ .
- At the end of $ i = 4 $ , $ A = 8 $ and $ B = 3 $ .
- At the end of $ i = 5 $ , $ A = 11 $ and $ B = 3 $ .
Therefore, $ f(L, R, A, B) $ will return $ (11, 3) $ .For the second command, string $ S $ will be updated to "ABBBB".
For the third command, the value of $ A $ will always be $ 0 $ and the value of $ B $ will always be $ 1\,000\,000\,000 $ . Therefore, $ f(L, R, A, B) $ will return $ (0, 1\,000\,000\,000) $ .