A. Two 0-1 Sequencestime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputAquaMoon 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.InputThe 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.OutputFor 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).ExampleInput
106 2001001116 2110111016 2000001116 2111111018 510000101110107 4101000110018 6010100100100108 40101010110018 41010101001107 5101110011100Output
YES
YES
NO
NO
NO
YES
YES
NO
NO
YES
NoteIn 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.
106 2001001116 2110111016 2000001116 2111111018 510000101110107 4101000110018 6010100100100108 40101010110018 41010101001107 5101110011100
YES YES NO NO NO YES YES NO NO YES 
['constructive algorithms', 'greedy', '*800']