Czech ACM Student Chapter
Czech Technical University in Prague
Charles University in Prague
Technical University of Ostrava
acm
ˇ a
Slovak University of Technology
Pavol Jozef Saf´rik University in Koˇice
s
cz
ˇ
University of Zilina
Masaryk University
Matej Bel University in Bansk´ Bystrica
a
University of West Bohemia
CTU Open Contest 2016
Rotating Display
display.c, display.cpp, display.c11, Display.java, display.py
Wendy is finishing her summer job in the lab testing a new 3D printed robot which is being
taught to manipulate small objects.
To test the robot's abilities, a simple device called the display is used. It is a thin transparent
square array of N × N square slots. Each slot contains a token, in the shape of an ASCII
character (for better recognition), which is held in place in the slot by small magnets. The
display can be rotated by 90around the axis perpendicular to its surface or flipped by 180
around one of its four axes parallel to the display surface.
The robot simulates display rotations and flips by the following process. It removes the tokens
from their slots and puts them back into different slots so that the contents of the display looks
exactly as if the whole display was rotated or flipped. If, for achieving the desired effect, it is
necessary to rotate or to flip particular tokens in their new positions the robot does it as well.
The display remains stationary during the whole process.
For example, if the upper left corner of the display contains a token which looks like symbol "<"
(less than) then after flipping the display around the vertical axis this token is moved to the
upper right corner where it looks like the symbol ">" (greater than). Then, after left rotation
the same token is moved back to the upper left corner where it looks like the symbol "^" (caret).
Wendy has programmed the robot to perform a long sequence of successive flips and rotations.
To check the correctness of the robot's algorithms, she needs to know in advance how the display
should look when the robot finishes its work.
Input Specification
We suppose that a token on the display can be shaped as any of the following so called symmetric
characters: "<", ">", "^", "v", "o", "x", "|", "-", "/", "\". When a symmetric character is
rotated or flipped it either remains the same or it becomes another symmetric character whose
shape is the most similar to the rotated/flipped one.
There are more test cases. Each case starts with a line containing one integer N (1 N 100).
Next, there are N lines representing the initial state of the display. Each line contains a string
which consists of exactly N symmetric characters. Each character represents one slot on the
display and the order of symbols in the input corresponds to the order of the tokens on the
display. No slot on the display is empty. After N lines, there is a line with a command string
specifying the flips and rotations that has to be carried out. A command string consists of
command characters, each command character specifies one rotation or flip as follows: "<"
(rotation left), ">" (rotation right), "-" (flip around horizontal axis), "|" (flip around vertical
axis), "\" (flip around main diagonal), "/" (flip around anti-diagonal). Two successive command
characters are separated by single space. The robot has to respect the order of commands in
the command string. The number of commands is always positive and at most 106.
The decimal ASCII codes of the characters relevant to this problem are 45 ("-"), 47 ("/"), 60
("<"), 62 (">"), 92 ("\"), 94 ("^"), 111 ("o"), 118 ("v"), 120 ("x"), 124 ("|").
Output Specification
For each test case, print N lines specifying the final position and orientation of the tokens on
the display. The output format of the display representation is identical to the input format
except for the size of the display which should not be printed.
Sample Input
3
o^-
/v|
vx^
<|
5
x>-o\
voooo
|ooo/
ooo/v
\o/vv
|\|
Output for Sample Input
>-|
x<>
</o
<</o\
</ooo
/ooo|
oooo^
\o-<x