A11899. Obtaining the String
编程题
普及/提高-
知识点
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 $t$ .
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.
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.
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 #1
6 abcdef abdfec
输出 #1
4 3 5 4 5
输入 #2
4 abcd accd
输出 #2
-1
说明/提示
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.
In the second example there is no way to transform the string $s$ into the string $t$ through any allowed moves.