[BOJ 6935] Post's Correspondence Problem
View as PDFLet $A$ and $B$ be two sequences of non-empty strings:</p>
\[\displaystyle \begin{align*} A &= (a_1, a_2, \dots, a_n) \\ B &= (b_1, b_2, \dots, b_n) \end{align*}\]
Let $m$ be a positive integer. Does there exist a sequence of integers $i_1, i_2, \dots, i_k$ such that $m > k > 0$ and $a_{i_1} a_{i_2} \dots a_{i_k} = b_{i_1} b_{i_2} \dots b_{i_k}$?
For example, if $A = (a, abaaa, ab)$ and $B = (aaa, ab, b)$, then the required sequence of integers is $(2, 1, 1, 3)$ giving $abaaaaaab = abaaaaaab$.
입력 형식
The first two lines of input will contain $m$ and $n$ respectively, and $m \times n \le 40$. The next $2n$ lines contain in order the elements of $A$ followed by the elements of $B$. Each string is at most $20$ characters.
출력 형식
If a solution exists, print $k$ on a line by itself, followed by the integer sequence in order, one element per line. Otherwise, print a single line containing No solution..
예제 입력 1
7
3
a
abaaa
ab
aaa
ab
b
예제 출력 1
4
2
1
1
3
예제 입력 2
10
3
abc
def
ghi
bcd
efg
hia
예제 출력 2
No solution.
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