codeforces#P1704A. Two 0-1 Sequences
Two 0-1 Sequences
Description
AquaMoon has two binary sequences $a$ and $b$, which contain only $0$ and $1$. AquaMoon can perform the following two operations any number of times ($a_1$ is the first element of $a$, $a_2$ is the second element of $a$, and so on):
- Operation 1: if $a$ contains at least two elements, change $a_2$ to $\operatorname{min}(a_1,a_2)$, and remove the first element of $a$.
- Operation 2: if $a$ contains at least two elements, change $a_2$ to $\operatorname{max}(a_1,a_2)$, and remove the first element of $a$.
Note that after a removal of the first element of $a$, the former $a_2$ becomes the first element of $a$, the former $a_3$ becomes the second element of $a$ and so on, and the length of $a$ reduces by one.
Determine if AquaMoon can make $a$ equal to $b$ by using these operations.
The first line contains a single integer $t$ ($1 \leq t \leq 2\,000$) — the number of test cases. Description of test cases follows.
The first line of each test case contains two integers $n$, $m$ ($1 \leq n,m \leq 50$, $m \leq n$) — the lengths of $a$ and $b$ respectively.
The second line of each test case contains a string $a$ of length $n$, consisting only $0$ and $1$.
The third line of each test case contains a string $b$ of length $m$, consisting only $0$ and $1$.
For each test case, output "YES" if AquaMoon can change $a$ to $b$ by using these options; otherwise, output "NO".
You may print each letter in any case (for example, "YES", "Yes", "yes", "yEs" will all be recognized as a positive answer).
Input
The first line contains a single integer $t$ ($1 \leq t \leq 2\,000$) — the number of test cases. Description of test cases follows.
The first line of each test case contains two integers $n$, $m$ ($1 \leq n,m \leq 50$, $m \leq n$) — the lengths of $a$ and $b$ respectively.
The second line of each test case contains a string $a$ of length $n$, consisting only $0$ and $1$.
The third line of each test case contains a string $b$ of length $m$, consisting only $0$ and $1$.
Output
For each test case, output "YES" if AquaMoon can change $a$ to $b$ by using these options; otherwise, output "NO".
You may print each letter in any case (for example, "YES", "Yes", "yes", "yEs" will all be recognized as a positive answer).
Samples
10
6 2
001001
11
6 2
110111
01
6 2
000001
11
6 2
111111
01
8 5
10000101
11010
7 4
1010001
1001
8 6
01010010
010010
8 4
01010101
1001
8 4
10101010
0110
7 5
1011100
11100
YES
YES
NO
NO
NO
YES
YES
NO
NO
YES
Note
In the first test case, you can use Operation 2 four times to make $a$ equals to $b$.
In the second test case, you can use Operation 1 four times to make $a$ equals to $b$.
In the third test case, it can be proved that no matter how we use the operations, it is impossible to make $a$ equal to $b$.
In the fourth test case, it can be proved that no matter how we use the operations, it is impossible to make $a$ equal to $b$.
In the fifth test case, you can use Operation 2 three times to make $a$ become $10101$, so the first element of $a$ equals to the first element of $b$, but it can be proved that no matter how to operate, the second to the fifth elements of $a$ can't be the same as $b$.