#include <iostream>
#include <string>
using namespace std;
 
bool canBeMadeEqual(const string& s, const string& t) {
    int i = 0, j = 0;
 
    // 尝试在 s 中匹配 t
    while (i < s.size() && j < t.size()) {
        if (s[i] == t[j]) {
            j++;
        }
        i++;
    }
 
    return j == t.size(); // 如果完全匹配 t，则返回 true
}
 
int main() {
    int T;
    cin >> T;
 
    while (T--) {
        int m, n;
        cin >> m >> n;
        string s, t;
        cin >> s >> t;
 
        if (canBeMadeEqual(s, t)) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
 
    return 0;
}
 

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4 2
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