Read the input one line at a time until you have read all n lines. Now output the minimum line out of the first floor(n/2) lines (where smaller is with respect to the usual order on Strings, as defined by String.compareTo()). If n <= 1 you should output the empty string.

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.List; import java.util.ArrayList; public class Part3 { /** * 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 { // TODO: Your code goes here - see Part0 for an example } /** * 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: " + 1e-9 * (stop-start)); } catch (IOException e) { System.err.println(e); System.exit(-1); } } }