Codeforces Round 278 (Div. 1)
D
Conveyor Belts
Codeforces
2700
原题
← CE →
翻译中…

Automatic Bakery of Cyberland (ABC) recently bought an $*n* × *m*$ rectangle table. To serve the diners, ABC placed seats around the table. The size of each seat is equal to a unit square, so there are $2(*n* + *m*)$ seats in total.

翻译中…

ABC placed conveyor belts on each unit square on the table. There are three types of conveyor belts: "^", "<" and ">". A "^" belt can bring things upwards. "<" can bring leftwards and ">" can bring rightwards.

翻译中…

Let's number the rows with $1$ to $*n*$ from top to bottom, the columns with $1$ to $*m*$ from left to right. We consider the seats above and below the top of the table are rows $0$ and $*n* + 1$ respectively. Also we define seats to the left of the table and to the right of the table to be column $0$ and $*m* + 1$. Due to the conveyor belts direction restriction there are currently no way for a diner sitting in the row $*n* + 1$ to be served.

翻译中…

Given the initial table, there will be $*q*$ events in order. There are two types of events:

翻译中…
  • "A $*x*$ $*y*$" means, a piece of bread will appear at row $*x*$ and column $*y*$ (we will denote such position as $(*x*, *y*)$). The bread will follow the conveyor belt, until arriving at a seat of a diner. It is possible that the bread gets stuck in an infinite loop. Your task is to simulate the process, and output the final position of the bread, or determine that there will be an infinite loop.
  • "C $*x*$ $*y*$ $*c*$" means that the type of the conveyor belt at $(*x*, *y*)$ is changed to $*c*$.
翻译中…

Queries are performed separately meaning that even if the bread got stuck in an infinite loop, it won't affect further queries.

翻译中…

Input

翻译中…

The first line of input contains three integers $*n*$, $*m*$ and $*q*$ ($1 ≤ *n* ≤ 10^{5}, 1 ≤ *m* ≤ 10, 1 ≤ *q* ≤ 10^{5}$), separated by a space.

翻译中…

Next $*n*$ lines, each line contains $*m*$ characters, describing the table. The characters can only be one of "<^>".

翻译中…

Next $*q*$ lines, each line describes an event. The format is "C x y c" or "A x y" (Consecutive elements are separated by a space). It's guaranteed that $1 ≤ *x* ≤ *n*, 1 ≤ *y* ≤ *m*$. $*c*$ is a character from the set "<^>".

翻译中…

There are at most $10000$ queries of "C" type.

翻译中…

Output

翻译中…

For each event of type "A", output two integers $*tx*$, $*ty*$ in a line, separated by a space, denoting the destination of $(*x*, *y*)$ is $(*tx*, *ty*)$.

翻译中…

If there is an infinite loop, you should output $*tx* = *ty* =  - 1$.

翻译中…

Note

翻译中…

For the first sample:

翻译中…

If the bread goes from $(2, 1)$, it will go out of the table at $(1, 3)$.

翻译中…

After changing the conveyor belt of $(1, 2)$ to "<", when the bread goes from $(2, 1)$ again, it will get stuck at "><", so output is $( - 1,  - 1)$.

翻译中…

样例

Input #1
2 2 3
>>
^^
A 2 1
C 1 2 <
A 2 1
Output #1
1 3
-1 -1
InputCopy OutputCopy
Input #2
4 5 7
><<^<
^<^^>
>>>^>
>^>>^
A 3 1
A 2 2
C 1 4 <
A 3 1
C 1 2 ^
A 3 1
A 2 2
Output #2
0 4
-1 -1
-1 -1
0 2
0 2
InputCopy OutputCopy
题目信息
题号
487D
时间限制
3 s
内存限制
256 MB
标签
数据结构

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。