CF1701B.Permutation
普及/提高-
通过率:0%
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题目描述
Recall that a permutation of length n is an array where each element from 1 to n occurs exactly once.
For a fixed positive integer d , let's define the cost of the permutation p of length n as the number of indices i (1≤i<n) such that pi⋅d=pi+1 .
For example, if d=3 and p=[5,2,6,7,1,3,4] , then the cost of such a permutation is 2 , because p2⋅3=p3 and p5⋅3=p6 .
Your task is the following one: for a given value n , find the permutation of length n and the value d with maximum possible cost (over all ways to choose the permutation and d ). If there are multiple answers, then print any of them.
输入格式
The first line contains a single integer t ( 1≤t≤500 ) — the number of test cases.
The single line of each test case contains a single integer n ( 2≤n≤2⋅105 ).
The sum of n over all test cases does not exceed 2⋅105 .
输出格式
For each test case, print the value d in the first line, and n integers in the second line — the permutation itself. If there are multiple answers, then print any of them.
输入输出样例
输入#1
2 2 3
输出#1
2 1 2 3 2 1 3