Question

Java only. Thanks

These questions involve choosing the right abstraction (Collection, Set, List, Queue, Deque, SortedSet, Map, or SortedMap) to EFFICIENTLY accomplish the task at hand. The best way to do these is to read the question and then think about what type of Collection is best to use to solve it. There are only a few lines of code you need to write to solve each of them.

Unless specified otherwise, sorted order refers to the natural sorted order on Strings, as defined by String.compareTo(s).

DONT MODIFY MAIN

1. [5 marks] Read the input one line at a time. When you are done, output all the lines in case-insensitive sorted order.

package comp2402a1;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class Part1 {
   
   /**
    * @param r the reader to read from
    * @param w the writer to write to
    * @throws IOException
    */
   public static void doIt(BufferedReader r, PrintWriter w) throws IOException {
        //Code goes here
        }


   /**
    * The driver.  Open a BufferedReader and a PrintWriter, either from System.in
    * and System.out or from filenames specified on the command line, then call doIt.
    * @param args
    */
   public static void main(String[] args) {
      try {
         BufferedReader r;
         PrintWriter w;
         if (args.length == 0) {
            r = new BufferedReader(new InputStreamReader(System.in));
            w = new PrintWriter(System.out);
         } else if (args.length == 1) {
            r = new BufferedReader(new FileReader(args[0]));
            w = new PrintWriter(System.out);            
         } else {
            r = new BufferedReader(new FileReader(args[0]));
            w = new PrintWriter(new FileWriter(args[1]));
         }
         long start = System.nanoTime();
         doIt(r, w);
         w.flush();
         long stop = System.nanoTime();
         System.out.println("Execution time: " + 10e-9 * (stop-start));
      } catch (IOException e) {
         System.err.println(e);
         System.exit(-1);
      }
   }
}

EXAMPLE:

package comp2402a1;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

public class Part0 {
   
   /**
    * Read lines one at a time from r.  After reading all lines, output
    * all lines to w, outputting duplicate lines only once.  Note: the order
    * of the output is unspecified and may have nothing to do with the order
    * that lines appear in r.
    * @param r the reader to read from
    * @param w the writer to write to
    * @throws IOException
    */
   public static void doIt(BufferedReader r, PrintWriter w) throws IOException {
        Set<String> s = new HashSet<>();

        for (String line = r.readLine(); line != null; line = r.readLine()) {
            s.add(line);
        }

        for (String text : s) {
            w.println(text);
        }
   }

   /**
    * The driver.  Open a BufferedReader and a PrintWriter, either from System.in
    * and System.out or from filenames specified on the command line, then call doIt.
    * @param args
    */
   public static void main(String[] args) {
      try {
         BufferedReader r;
         PrintWriter w;
         if (args.length == 0) {
            r = new BufferedReader(new InputStreamReader(System.in));
            w = new PrintWriter(System.out);
         } else if (args.length == 1) {
            r = new BufferedReader(new FileReader(args[0]));
            w = new PrintWriter(System.out);            
         } else {
            r = new BufferedReader(new FileReader(args[0]));
            w = new PrintWriter(new FileWriter(args[1]));
         }
         long start = System.nanoTime();
         doIt(r, w);
         w.flush();
         long stop = System.nanoTime();
         System.out.println("Execution time: " + 10e-9 * (stop-start));
      } catch (IOException e) {
         System.err.println(e);
         System.exit(-1);
      }
   }
}

Answer 1

Collection.shuffle(LIST) which permute the list elements

CODE

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

//6) Read the entire input one line at a time and then output the even numbered lines
// (starting with the first line, line 0) followed by the odd-numbered lines. The order even lines (and odd lines) should be the same as they appeared in the input.

class Part8 {

/**
* Your code goes here - see Part0 for an example
* @param r the reader to read from
* @param w the writer to write to
* @throws IOException
*/
public static void doIt(BufferedReader r, PrintWriter w) throws IOException {
// Your code goes here - see Part0 for an example

List<String> list = new ArrayList<>();

for (String line = r.readLine(); line != null; line = r.readLine()) {
list.add(line);
}

Collections.shuffle(list);

for (String str :
list) {
w.println(str);
}

}

/**
* The driver. Open a BufferedReader and a PrintWriter, either from System.in
* and System.out or from filenames specified on the command line, then call doIt.
* @param args
*/
public static void main(String[] args) {
try {
BufferedReader r;
PrintWriter w;
if (args.length == 0) {
r = new BufferedReader(new InputStreamReader(System.in));
w = new PrintWriter(System.out);
} else if (args.length == 1) {
r = new BufferedReader(new FileReader(args[0]));
w = new PrintWriter(System.out);
} else {
r = new BufferedReader(new FileReader(args[0]));
w = new PrintWriter(new FileWriter(args[1]));
}

r = new BufferedReader(new FileReader("abc.ser"));
w = new PrintWriter(new FileWriter("ooo.txt"));

long start = System.nanoTime();
doIt(r, w);
w.flush();
long stop = System.nanoTime();
System.out.println("Execution time: " + 10e-9 * (stop-start));
} catch (IOException e) {
System.err.println(e);
System.exit(-1);
}
}
}

INPUT 0 is a is a 2 is a 3 is a 4 is a 5 is a 6 is a 7 is a is a 7 is a 4 is a 8 is a 3 is a 8 is a 6 is a 2 is a 5 is a OUTPUT 2 is a 6 is a 2 is a 4 is a 3 is a 5 is a 8 is a 0 is a 1 is a