Prefix Subsequences.cpp

// { Driver Code Starts
// Initial Template for C++

#include <bits/stdc++.h>
using namespace std;

// } Driver Code Ends
// User function Template for C++

class Solution
{
public:
    int maximumPrefix(int n, int m, string s, string t)
    {
        // code here
        int j = 0;
        for (int i = 0; i < n; i++)
        {
            bool flag = false;
            while (j < m)
            {
                if (t[j] == s[i])
                {
                    flag = true;
                    j++;
                    break;
                }
                j++;
            }
            if (flag == false)
            {
                return i + 1;
            }
        }
        return -1;
    }
};

// { Driver Code Starts.

int main()
{
    int c;
    cin >> c;
    while (c--)
    {
        int n, m;
        cin >> n >> m;
        string s, t;
        cin >> s >> t;
        Solution obj;
        int ans = obj.maximumPrefix(n, m, s, t);
        cout << ans << "\n";
    }

    return 0;
}
// } Driver Code Ends