Question

I’m solving UVA’s Edit Step Ladders on an uva sub-site named programming-challenges.com, but since I didn’t get at all the format in which I’m supposed to test-input I simply took their sample input, put it into a text file and tested my code from there. Like this:

import java.io.*;
import java.util.*;

class Levenshtein {
    private static int minimum(int a, int b, int c) {
        if(a<=b && a<=c)
            return a;
        if(b<=a && b<=c)
            return b;
        return c;
    }

public static int computeLevenshteinDistance(String str1, String str2) {
    return computeLevenshteinDistance(str1.toCharArray(),
                                      str2.toCharArray());
}

private static int computeLevenshteinDistance(char [] str1, char [] str2) {
    int [][]distance = new int[str1.length+1][str2.length+1];

    for(int i=0;i<=str1.length;i++)
            distance[i][0]=i;

    for(int j=0;j<=str2.length;j++)
        distance[0][j]=j;

    for(int i=1;i<=str1.length;i++)
        for(int j=1;j<=str2.length;j++)
            distance[i][j]= minimum(distance[i-1][j]+1,
                                    distance[i][j-1]+1,
                                    distance[i-1][j-1]+
                                    ((str1[i-1]==str2[j-1])?0:1));

    return distance[str1.length][str2.length];
}

public static void main(String args[]){

ArrayList<String> theWords = new ArrayList<String>();

try {

        String ruta="entradaLevenshtein.txt";
        File myFile = new File (ruta);
        FileReader fileReader = new FileReader(myFile);

        BufferedReader reader = new BufferedReader(fileReader);

        String line = null;

        while ((line=reader.readLine())!=null){
            System.out.println(line);
            theWords.add(line);
        }



        reader.close();
    }

    catch (IOException ex){
        ex.printStackTrace();

    }
 {}
 // todo esto sólo para iniciar el arreglo
 // ahora vienen las llamadas a Levenstein y las comparaciones

 int maxEdit=0;
 int actualEdit=0;

 int wordsIndex1 =0, wordsIndex2=0;


 while (wordsIndex1<= theWords.size())
 {
  while (wordsIndex2<= theWords.size()-1){
     actualEdit=computeLevenshteinDistance(theWords.get(wordsIndex1),theWords.get(wordsIndex2));
     if (actualEdit>maxEdit){maxEdit=actualEdit;}
     wordsIndex2++;
  }
 wordsIndex1++;

 }

 System.out.println(maxEdit+1);
}



}

my input file being:

cat
dig
dog
fig
fin
fine
fog
log
wine

I’m supposed to make the code comply to the following pattern, thing is..I don’t get where this thing is capturing its String:

import java.io.*;
import java.util.*;

class Modelo implements Runnable{
    static String ReadLn(int maxLength){  // utility function to read from stdin,
                                          // Provided by Programming-challenges, edit for style only
        byte line[] = new byte [maxLength];
        int length = 0;
        int input = -1;
        try{
            while (length < maxLength){//Read untill maxlength
                input = System.in.read();
                if ((input < 0) || (input == '\n')) break; //or untill end of line ninput
                line [length++] += input;
            }

            if ((input < 0) && (length == 0)) return null;  // eof
            return new String(line, 0, length);
        }catch (IOException e){
            return null;
        }
    }

    public static void main(String args[]) // entry point from OS
    {
        Modelo myWork = new Modelo();  // Construct the bootloader
        myWork.run();            // execute
    }

    public void run() {
        new myStuff().run();
    }
}
class myStuff implements Runnable{
    public void run(){
        try
        {

        /// PLACE YOUR JAVA CODE HERE




        }catch(Exception e){
            System.out.println("A Exception was generated");
        }
    }

    // You can insert more classes here if you want.
}

Why should I place it where it says //place your code here and not here??

 try{
                    while (length < maxLength){//Read untill maxlength
                        input = System.in.read();
                        if ((input < 0) || (input == '\n')) break; //or untill end of line input
                        line [length++] += input;

}

How do I manipulate the input??

Answer 1

I think the idea here is to write your program in the myStuff class, where it will be called in the run() method. From the run() method, you can use Modelo.ReadLn() to get your input.