Good Bye 2019
D
Strange Device
Codeforces
1900
原题
← CE →
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This problem is interactive.

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We have hidden an array $a$ of $n$ pairwise different numbers (this means that no two numbers are equal). You can get some information about this array using a new device you just ordered on Amazon.

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This device can answer queries of the following form: in response to the positions of $k$ different elements of the array, it will return the position and value of the $m$-th among them in the ascending order.

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Unfortunately, the instruction for the device was lost during delivery. However, you remember $k$, but don't remember $m$. Your task is to find $m$ using queries to this device.

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You can ask not more than $n$ queries.

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Note that the array $a$ and number $m$ are fixed before the start of the interaction and don't depend on your queries. In other words, interactor is not adaptive.

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Note that you don't have to minimize the number of queries, and you don't need to guess array $a$. You just have to guess $m$.

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Input

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The first line contains two integers $n$ and $k$ ($1\le k \lt n \le 500$) — the length of the array and the number of the elements in the query.

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It is guaranteed that number $m$ satisfies $1\le m \le k$, elements $a_1, a_2, \dots, a_n$ of the array satisfy $0\le a_i \le 10^9$, and all of them are different.

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Interaction

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You begin the interaction by reading $n$ and $k$.

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To ask a question about elements on positions $x_1, x_2, \dots, x_k$, in a separate line output

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$?$ $x_1$ $x_2$ $x_3$ ... $x_k$

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Numbers in the query have to satisfy $1 \le x_i \le n$, and all $x_i$ have to be different. Don't forget to 'flush', to get the answer.

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In response, you will receive two integers $pos$ and $a_{pos}$ — the position in the array $a$ of the $m$-th in ascending order element among $a_{x_1}, a_{x_2}, \dots, a_{x_k}$, and the element on this position.

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In case your query is invalid or you asked more than $n$ queries, the program will print $-1$ and will finish interaction. You will receive a Wrong answer verdict. Make sure to exit immediately to avoid getting other verdicts.

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When you determine $m$, output

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$!$ $m$

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After printing a query do not forget to output end of line and flush the output. Otherwise, you will get Idleness limit exceeded. To do this, use:

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  • fflush(stdout) or cout.flush() in C++;
  • System.out.flush() in Java;
  • flush(output) in Pascal;
  • stdout.flush() in Python;
  • see documentation for other languages.
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Hack format

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For the hacks use the following format:

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The first line has to contain three integers $n, k, m$ ($1 \le m \le k \lt n \le 500$) — the length of the array, number of elements in the query, and which in the ascending order number the device returns.

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In the next line output $n$ integers $a_1, a_2, \dots, a_n$ ($0\le a_i \le 10^9$) — the elements of the array. They have to be pairwise different.

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Note

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In the example, $n = 4$, $k = 3$, $m = 3$, $a = [2, 0, 1, 9]$.

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样例

Input #1
4 3
4 9
4 9
4 9
1 2
Output #1
? 2 3 4
? 1 3 4
? 1 2 4
? 1 2 3
! 3
InputCopy OutputCopy
题目信息
题号
1270D
所属比赛
时间限制
1 s
内存限制
256 MB
标签
构造
交互题
数学
排序

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。