301342: CF251B. Playing with Permutations
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
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Description
Playing with Permutations
题意翻译
现在你有一个长为 $n$ 的序列 $q$ 以及另外一个长度为 $n$ 的序列 $p$ 。其中 $p$ 序列初始化为 $1,2,3,....n$ 定义两种操作: $1.p[q[i]]=p[i]$ $2.p[i]=p[q[i]]$ 给出步骤数 $k$ 和目标序列 $s$ ,问你能否在恰好 $k$ 个操作后实现从 $p$ 序列到 $s$ 序列的转换? 输出"YES"或者"NO"(不含引号)来表示你的结果。 要求:在 $k$ 步以前的过程中不能让 $p=s$ ,否则视作失败,哪怕是刚开始 $p=s$ 也不行。 输入格式: 第一行两个整数 $n,k$ ($1<=n,k<=100$) 第二行以空格隔开的 $n$ 个数字,表示序列 $q$ 第三行以空格隔开的 $n$ 个数字,表示序列 $s$ 输出格式 仅一行,"YES"或"NO"(不含引号)表示结果。题目描述
Little Petya likes permutations a lot. Recently his mom has presented him permutation $ q_{1},q_{2},...,q_{n} $ of length $ n $ . A permutation $ a $ of length $ n $ is a sequence of integers $ a_{1},a_{2},...,a_{n} $ $ (1<=a_{i}<=n) $ , all integers there are distinct. There is only one thing Petya likes more than permutations: playing with little Masha. As it turns out, Masha also has a permutation of length $ n $ . Petya decided to get the same permutation, whatever the cost may be. For that, he devised a game with the following rules: - Before the beginning of the game Petya writes permutation $ 1,2,...,n $ on the blackboard. After that Petya makes exactly $ k $ moves, which are described below. - During a move Petya tosses a coin. If the coin shows heads, he performs point 1, if the coin shows tails, he performs point 2. 1. Let's assume that the board contains permutation $ p_{1},p_{2},...,p_{n} $ at the given moment. Then Petya removes the written permutation $ p $ from the board and writes another one instead: $ p_{q1},p_{q2},...,p_{qn} $ . In other words, Petya applies permutation $ q $ (which he has got from his mother) to permutation $ p $ . 2. All actions are similar to point 1, except that Petya writes permutation $ t $ on the board, such that: $ t_{qi}=p_{i} $ for all $ i $ from 1 to $ n $ . In other words, Petya applies a permutation that is inverse to $ q $ to permutation $ p $ . We know that after the $ k $ -th move the board contained Masha's permutation $ s_{1},s_{2},...,s_{n} $ . Besides, we know that throughout the game process Masha's permutation never occurred on the board before the $ k $ -th move. Note that the game has exactly $ k $ moves, that is, throughout the game the coin was tossed exactly $ k $ times. Your task is to determine whether the described situation is possible or else state that Petya was mistaken somewhere. See samples and notes to them for a better understanding.输入输出格式
输入格式
The first line contains two integers $ n $ and $ k $ ( $ 1<=n,k<=100 $ ). The second line contains $ n $ space-separated integers $ q_{1},q_{2},...,q_{n} $ ( $ 1<=q_{i}<=n $ ) — the permutation that Petya's got as a present. The third line contains Masha's permutation $ s $ , in the similar format. It is guaranteed that the given sequences $ q $ and $ s $ are correct permutations.
输出格式
If the situation that is described in the statement is possible, print "YES" (without the quotes), otherwise print "NO" (without the quotes).
输入输出样例
输入样例 #1
4 1
2 3 4 1
1 2 3 4
输出样例 #1
NO
输入样例 #2
4 1
4 3 1 2
3 4 2 1
输出样例 #2
YES
输入样例 #3
4 3
4 3 1 2
3 4 2 1
输出样例 #3
YES
输入样例 #4
4 2
4 3 1 2
2 1 4 3
输出样例 #4
YES
输入样例 #5
4 1
4 3 1 2
2 1 4 3
输出样例 #5
NO