301906: CF361B. Levko and Permutation
Memory Limit:256 MB
Time Limit:1 S
Judge Style:Text Compare
Creator:
Submit:0
Solved:0
Description
Levko and Permutation
题意翻译
给定 $n,k$,你需要构造一个序列,使得集合 $\{i|_{1\le i \le n,gcd(i,a_i)>1}\}$ 的元素个数恰好为 $k$。题目描述
Levko loves permutations very much. A permutation of length $ n $ is a sequence of distinct positive integers, each is at most $ n $ . Let’s assume that value $ gcd(a,b) $ shows the greatest common divisor of numbers $ a $ and $ b $ . Levko assumes that element $ p_{i} $ of permutation $ p_{1},p_{2},...\ ,p_{n} $ is good if $ gcd(i,p_{i})>1 $ . Levko considers a permutation beautiful, if it has exactly $ k $ good elements. Unfortunately, he doesn’t know any beautiful permutation. Your task is to help him to find at least one of them.输入输出格式
输入格式
The single line contains two integers $ n $ and $ k $ ( $ 1<=n<=10^{5} $ , $ 0<=k<=n $ ).
输出格式
In a single line print either any beautiful permutation or -1, if such permutation doesn’t exist. If there are multiple suitable permutations, you are allowed to print any of them.
输入输出样例
输入样例 #1
4 2
输出样例 #1
2 4 3 1
输入样例 #2
1 1
输出样例 #2
-1