You are rocking the latest breakthrough in Computer Science: animated fonts. Suddenly, all of your colleagues' code looks amazing, and you are finally motivated to review it. Unfortunately, due to the constant rotations, it is hard to distinguish between the (plus) and the (multiply) operators (all the other characters are still readable). The function you are reviewing takes as input integers and returns the value
,
where the operators are either or . For example when given input with hidden operators , then the function returns .
You can still execute the function a few times on some input and read the returned value. Use this to recover the operators.
Interaction
This is an interactive problem. Your submission will be run against an interactor, which reads the standard output of your submission and writes to the standard input of your submission. This interaction needs to follow a specific protocol:
The interactor first sends one line containing one integer , the number of hidden operators.
Then, your program should make at most queries to determine the operators. Each query
is made by printing one line of the form ? a_0 a_1 ... a_n
. The interactor
will respond by printing one line with an integer, the value of
,
Make sure you flush the buffer after each write.
When you have determined the operators, print a single line of the form ! s
, where is a
string consisting of exactly characters, which are all +
(plus) or x
(multiply). The th
character of this string should be . This line does not count as one of your queries.
Using more than queries will result in a wrong answer verdict.
Sample Interaction 1
>>>
denotes your output. Do not print this out.
2
>>> ? 1 1 2
4
>>> ? 1 1 3
6
! +x
Sample Interaction 2
>>>
denotes your output. Do not print this out.
10
>>> ? 1 1 1 1 1 1 1 1 1 1 1
5
>>> ? 0 4 2 4 2 4 2 4 2 4 2
6224
>>> ? 1 2 3 4 5 6 7 8 9 10 11
640750
>>> ! ++xxx+x+xx
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