mimetypes.cpp

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

string ToLower(string str)
{
    for(auto& c : str)
    {
        c = tolower(c);
    }

    return str;
}

string GetFileExtension(string fileName)
{
    const char fileExtensionDelimiter = '.';
   
    int delimLocation = fileName.find_last_of(fileExtensionDelimiter);;
    if (delimLocation == -1)
        return "";

    else return fileName.substr(delimLocation + 1);
}

std::unordered_map<string, string> MimeTypes;
const string UnknownType = "UNKNOWN";
string LookupMimeType(string extension)
{
    auto mimeTypeIter = MimeTypes.find(extension);
    string found = mimeTypeIter != MimeTypes.end() ? mimeTypeIter->second : UnknownType;
    return mimeTypeIter != MimeTypes.end() ? mimeTypeIter->second : UnknownType;
}

/**
 * Auto-generated code below aims at helping you parse
 * the standard input according to the problem statement.
 **/
int main()
{

    int n; // Number of elements which make up the association table.
    cin >> n; cin.ignore();
    int q; // Number Q of file names to be analyzed.
    cin >> q; cin.ignore();
    
    for (int i = 0; i < n; i++) {
        string ext; // file extension
        string mt; // MIME type.
        
        cin >> ext >> mt; cin.ignore();
        ext = ToLower(ext);
        MimeTypes.insert_or_assign(ext, mt);
    }

    for (int i = 0; i < q; i++) {
        string fname;
        getline(cin, fname); // One file name per line.
        fname = ToLower(GetFileExtension(fname));
        cout << LookupMimeType(fname) << endl;
    }
}