Problem E: Logo 2
Logo is a programming language built around a turtle. Commands in the
language cause the turtle to move. The turtle has a pen attached to it.
As the turtle moves, it draw lines on the page. The turtle can be programmed
to draw interesting pictures.
We are interested in making the turtle draw a picture, then return to
the point that it started from. For example, we could give the turtle
the following program:
fd 100 lt 120 fd 100 lt 120 fd 100
The command fd causes the turtle to move forward by the
specified number of units. The command lt causes the turtle to
turn left by the specified number of degrees. Thus the above commands
cause the turtle to draw an equilateral triangle with sides 100 units
long. Notice that after executing the commands, the turtle ends up
in the same place as it started.
The turtle understands
two additional commands.
The command bk causes the turtle to move backward by the
specified number of units. The command rt causes the turtle to
turn right by the specified number of degrees. The distances and angles
in all commands are always non-negative integers.
Unfortunately, we have been messy in writing the program down, and
cannot read our own writing. One of the numbers in the program
is missing. Assuming the turtle ends up at the place that it started
at the end of its journey, can you find the missing number?
Input Specification
The first line of input contains one integer specifying the number of
test cases to follow.
Each test case starts with a line containing
one integer, the number of commands to follow. The commands follow,
one on each line. Each test case will contain no more than 1000 commands.
The argument of each command is either an integer
or a question mark (?). There will be exactly one question
mark in each test case.
Sample Input
1
5
fd 100
lt 120
fd ?
lt 120
fd 100
Output Specification
For each test case, output line containing a single integer n
such that when the question mark in the program is replaced by n,
the turtle ends up at the same point that it started from once the
program completes. If the question mark is the argument of an
lt or rt command, the angle in the output must be between 0
and 359 degrees, inclusive. The correct answer will always be
an integer, and we guarantee that for every test case, there
will be only one correct answer.
Output for Sample Input
100
Ondřej Lhoták