Hackerrank Append and Delete

    if (s==t && k%2==0) return "Yes";
    if(k>=s.size()+t.size()) return "Yes";
    int s_size=0;
    for(int i=0;i<s.size();i++){
        if (s[i]!=t[i]){
            s=s.substr(i);
            s_size=s.size();
            t=t.substr(i);
            break;
        }
        if(i==s.size()-1 && t.size()>s.size()){
            s_size=0;
            t=t.substr(i+1);
            break;
        }
    }
    if ( k<s_size+t.size()) return "No";
    if(  (k-(s_size+t.size()) )%2==0 ) return "Yes";
    return "No";
}