P17447 A Simple Construction Problem
Description
A "Hongzhuan sequence" of length $n$ is a sequence that satisfies the following properties:
- Each integer from $1$ to $n$ appears in the sequence exactly once.
- The sum of every pair of adjacent elements is not a perfect square.
Given an integer $n$, construct a "Hongzhuan sequence" of length $n$.
Input Format
The first line contains an integer $T$ ($1\le T\le 10^4$), meaning the number of test cases.
For each test case, there is only one line containing one integer $n$ ($1\le n\le 4\times 10^6$), meaning the length of the "Hongzhuan sequence" to construct.
It is guaranteed that the sum of all $n$ does not exceed $4\times 10^6$. It can be proven that under the given conditions, a solution always exists.
Output Format
Output $T$ lines. Each line should be the constructed sequence. If there are multiple solutions, output any one.
Explanation/Hint
For $n = 5$, if the output is `1 2 3 4 5`, it is wrong, because $4 + 5 = 9$ is a perfect square.
Translated by ChatGPT 5