URI Online Judge | 1636

Cyclic Antimonotonic Permutations

Local Contest, University of Ulm Germany

Timelimit: 4

A permutation is a sequence of integers which contains each integer from 1 to n exactly once. In this problem we are looking for permutations with special properties:

1. Antimonotonic: for each consecutive 3 values pi-1, pi, pi+1 (1 < i < n), pi should either be the smallest or the biggest of the three values.
2. Cyclic: The permutation should consist of only one cycle, that is, when we use pi as a pointer from i to pi, it should be possible to start at position 1 and follow the pointers and reach all n positions before returning to position 1.

Input

The input file contains several test cases. Each test case consists of a line containing an integer n, (3 ≤ n ≤ 106), the number of integers in the permutation. Input is terminated by n = 0.

Output

For each test case print a permutation of the integers 1 to n which is both antimonotonic and cyclic. In case there are multiple solutions, you may print any one. Separate all integers by whitespace characters.

 Sample Input Sample Output 3 5 10 0 3 1 2 4 5 2 3 1 6 10 2 9 3 5 4 7 1 8