HackerEarth Find the String problem solution

In this HackerEarth Find the String problem solution You are given a matrix of characters. The matrix has N rows and M columns. Given a string s, you have to tell if it is possible to generate that string from given matrix.

Rules for generating string from matrix are:

You have to pick first character of string from row 1, second character from row 2 and so on. The  character of string is to be picked from row 1, that is, you can traverse the (N + 1)th rows in a cyclic manner (row 1 comes after row N).

If an occurrence of a character is picked from a row, you cannot pick the same occurrence again from that row.

You have to print Yes if given string can be generated from matrix using the given rules, else print No.

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n,m;
        string s;
        cin>>n>>m;
        int f[1005][26]={0};
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
            {
                char temp;
                cin>>temp;
                f[i][temp-'a']++;
            }
        }
        cin>>s;
        bool check=1;
        for(int i=0;i<s.size() && f;i++)
        {
            int lev=i%n;
            if(f[lev][s[i]-'a'])f[lev][s[i]-'a']--;
            else check=0;
        }
        if(check)cout<<"Yesn";
        else cout<<"Non";
    }
    return 0;
}