#include <iostream>
#include <string>
using namespace std;
 
bool isSubsequence(string s, string t) {
    int n = s.size(), m = t.size();
    int i = 0, j = 0;
 
    while (i < n && j < m) {
        if (s[i] == t[j]) {
            j++; // Move pointer in t
        }
        i++; // Always move pointer in s
    }
 
    return j == m; // If we've matched all characters of t
}
 
int main() {
    int T; // Number of test cases
    cin >> T;
 
    while (T--) {
        int n, m;
        string s, t;
 
        cin >> n >> m;  // Lengths of the strings
        cin >> s >> t;  // The two strings
 
        if (isSubsequence(s, t)) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
 
    return 0;
}
 

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