Obtaining the String

题意翻译

给定两个字符串s1,s2,只能交换s1的相邻元素，为最少需要次可以将s1换成s2.如果没有方法，输出-1.如果有方法，先输出步骤数，然后输出每一次移动的位置。步骤数要在10000以内

题目描述

You are given two strings $ s $ and $ t $ . Both strings have length $ n $ and consist of lowercase Latin letters. The characters in the strings are numbered from $ 1 $ to $ n $ . You can successively perform the following move any number of times (possibly, zero): - swap any two adjacent (neighboring) characters of $ s $ (i.e. for any $ i = \{1, 2, \dots, n - 1\} $ you can swap $ s_i $ and $ s_{i + 1}) $ . You can't apply a move to the string $ t $ . The moves are applied to the string $ s $ one after another. Your task is to obtain the string $ t $ from the string $ s $ . Find any way to do it with at most $ 10^4 $ such moves. You do not have to minimize the number of moves, just find any sequence of moves of length $ 10^4 $ or less to transform $ s $ into $ t $ .

输入输出格式

输入格式

The first line of the input contains one integer $ n $ ( $ 1 \le n \le 50 $ ) — the length of strings $ s $ and $ t $ . The second line of the input contains the string $ s $ consisting of $ n $ lowercase Latin letters. The third line of the input contains the string $ t $ consisting of $ n $ lowercase Latin letters.

输出格式

If it is impossible to obtain the string $ t $ using moves, print "-1". Otherwise in the first line print one integer $ k $ — the number of moves to transform $ s $ to $ t $ . Note that $ k $ must be an integer number between $ 0 $ and $ 10^4 $ inclusive. In the second line print $ k $ integers $ c_j $ ( $ 1 \le c_j < n $ ), where $ c_j $ means that on the $ j $ -th move you swap characters $ s_{c_j} $ and $ s_{c_j + 1} $ . If you do not need to apply any moves, print a single integer $ 0 $ in the first line and either leave the second line empty or do not print it at all.

输入输出样例

输入样例 #1

6
abcdef
abdfec

输出样例 #1

4
3 5 4 5 

输入样例 #2

4
abcd
accd

输出样例 #2

-1

说明

In the first example the string $ s $ changes as follows: "abcdef" $ \rightarrow $ "abdcef" $ \rightarrow $ "abdcfe" $ \rightarrow $ "abdfce" $ \rightarrow $ "abdfec". In the second example there is no way to transform the string $ s $ into the string $ t $ through any allowed moves.