Hello 2022
C
Hidden Permutations
Codeforces
1700
原题
← BD →
翻译中…

This is an interactive problem.

翻译中…

The jury has a permutation $p$ of length $n$ and wants you to guess it. For this, the jury created another permutation $q$ of length $n$. Initially, $q$ is an identity permutation ($q_i = i$ for all $i$).

翻译中…

You can ask queries to get $q_i$ for any $i$ you want. After each query, the jury will change $q$ in the following way:

翻译中…
  • At first, the jury will create a new permutation $q'$ of length $n$ such that $q'_i = q_{p_i}$ for all $i$.
  • Then the jury will replace permutation $q$ with pemutation $q'$.
翻译中…

You can make no more than $2n$ queries in order to quess $p$.

翻译中…

Input

翻译中…

The first line of input contains a single integer $t$ ($1 \leq t \leq 1000$) — the number of test cases.

翻译中…

Interaction

翻译中…

Interaction in each test case starts after reading the single integer $n$ ($1 \leq n \leq 10^4$) — the length of permutations $p$ and $q$.

翻译中…

To get the value of $q_i$, output the query in the format $?$ $i$ ($1 \leq i \leq n$). After that you will receive the value of $q_i$.

翻译中…

You can make at most $2n$ queries. After the incorrect query you will receive $0$ and you should exit immediately to get Wrong answer verdict.

翻译中…

When you will be ready to determine $p$, output $p$ in format $!$ $p_1$ $p_2$ $\ldots$ $p_n$. After this you should go to the next test case or exit if it was the last test case. Printing the permutation is not counted as one of $2n$ queries.

翻译中…

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:

翻译中…
  • 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.
翻译中…

It is guaranteed that the sum of $n$ over all test cases doesn't exceed $10^4$. The interactor is not adaptive in this problem.

翻译中…

Hacks:

翻译中…

To hack, use the following format:

翻译中…

The first line contains the single integer $t$ — the number of test cases.

翻译中…

The first line of each test case contains the single integer $n$ — the length of the permutations $p$ and $q$. The second line of each test case contains $n$ integers $p_1, p_2, \ldots, p_n$ — the hidden permutation for this test case.

翻译中…

Note

翻译中…

In the first test case the hidden permutation $p = [4, 2, 1, 3]$.

翻译中…

Before the first query $q = [1, 2, 3, 4]$ so answer for the query will be $q_3 = 3$.

翻译中…

Before the second query $q = [4, 2, 1, 3]$ so answer for the query will be $q_2 = 2$.

翻译中…

Before the third query $q = [3, 2, 4, 1]$ so answer for the query will be $q_4 = 1$.

翻译中…

In the second test case the hidden permutation $p = [1, 3, 4, 2]$.

翻译中…

Empty strings are given only for better readability. There will be no empty lines in the testing system.

翻译中…

样例

Input #1
2
4

3

2

1

4

2

4

4
Output #1
? 3

? 2

? 4

! 4 2 1 3

? 2

? 3

? 2

! 1 3 4 2
InputCopy OutputCopy
题目信息
题号
1621C
所属比赛
时间限制
1 s
内存限制
256 MB
标签
DFS 及类似
交互题
数学

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。