Question

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.TreeSet;

/**
 * MapSetLab - test the HashMap and TreeSet classes.
 * 
 * @author Michael Norton
 * @version 18 September 2018
 */
public class MapSetLab {
    
    /**
     * Main method.
     * 
     * @param args The command line arguments
     * @throws IOException The IOException
     */
    public static void main( String[] args ) throws IOException {
        
        // declarations & some instantiations
        BufferedReader reader = new BufferedReader( new InputStreamReader( 
                        System.in ) );
        HashMap< String, TreeSet< String > > networkMap = 
                        new HashMap< String, TreeSet< String> >();

        // reusable references
        String network;
        String tvShow;
        TreeSet< String > set;
        
        // get 10 network & tv show pairs
        for ( int i = 0; i < 10; i++ ) {
            
            // get values from user
            System.out.print(  "Enter TV network: " );
            network = reader.readLine();
            System.out.print( "Enter TV show on " + network + ": " );
            tvShow = reader.readLine();
            
            // if key not found, create new entry
            if ( !networkMap.containsKey( network ) ) {
                
                networkMap.put( network, new TreeSet<String>() );
            }
            
            // get the TreeSet from the HashMap and add the show to the network
            set = networkMap.get( network );
            set.add( tvShow );
            
            // print out the mapping
            System.out.println( networkMap );
            System.out.println();
        }
        
    }

}

Use an appropriate loop to ask the user to enter the name of a TV show and then print on a separate line the name of the network that maps to that show. Repeat until the user enters an empty string.

HINT: Iterate over each key (network) in the HashMap, and see if its value (set of shows) contains the desired show. If so, print out the network. If none of the networks have that show, report "UNKNOWN". You don't have to worry about uppercase/lowercase, just match the TV show name exactly.

Answer 1

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.HashMap;

import java.util.TreeSet;

/**

* MapSetLab - test the HashMap and TreeSet classes.

*

* @author Michael Norton

* @version 18 September 2018

*/

public class MapSetLab {

       /**

     * Main method.

     *

     * @param args The command line arguments

     * @throws IOException The IOException

     */

      

       public static void main(String[] args) throws IOException {

                // declarations & some instantiations

        BufferedReader reader = new BufferedReader( new InputStreamReader(

                        System.in ) );

        HashMap< String, TreeSet< String > > networkMap =

                        new HashMap< String, TreeSet< String> >();

        // reusable references

        String network;

        String tvShow;

        TreeSet< String > set;

       

     // get 10 network & tv show pairs

        for ( int i = 0; i < 10; i++ ) {

           

            // get values from user

            System.out.print( "Enter TV network: " );

            network = reader.readLine();

            System.out.print( "Enter TV show on " + network + ": " );

            tvShow = reader.readLine();

           

            // if key not found, create new entry

            if ( !networkMap.containsKey( network ) ) {

               

                networkMap.put( network, new TreeSet<String>() );

            }

           

            // get the TreeSet from the HashMap and add the show to the network

            set = networkMap.get( network );

            set.add( tvShow );

           

            // print out the mapping

            System.out.println( networkMap );

            System.out.println();

           

        }

       

        boolean found ;

        // loop that continues till the user exits

        while(true)

        {

             found = false;

             // input of tv show name

             System.out.print("Enter the TV show name : ");

             tvShow = reader.readLine();

             // check if user entered an empty string, then exit from loop

             if(tvShow.length() == 0)

                    break;

             // loop over the map

             for( String tvNetwork: networkMap.keySet())

             {

                    // check if this network contains the tv show, then print the network and exit from loop

                    if(networkMap.get(tvNetwork).contains(tvShow))

                    {

                           System.out.println(tvNetwork);

                           found=true;

                           break;

                    }

             }

            

             // check if tv show network was found, if not print "UNKNOWN"

             if(!found )

                    System.out.println("UNKNOWN");

        }

       

        reader.close();

       }

}

//end of MapSetLab.java

Output: