Question

Run-length encoding (RLE) is a simple "compression algorithm" (an algorithm which takes a block of data and reduces its size, producing a block that contains the same information in less space). It works by replacing repetitive sequences of identical data items with short "tokens" that represent entire sequences. Applying RLE to a string involves finding sequences in the string where the same character repeats. Each such sequence should be replaced by a "token" consisting of: the number of characters in the sequence the repeating character If a character does not repeat, it should be left alone. For example, consider the following string: After applying the RLE algorithm, this string is converted into: In the compressed string "9W" represents a sequence of 9 consecutive lowercase "w" characters. "5e" represents 5 consecutive lowercase "e" characters, etc. Write a method called compress that takes a sting as input, compresses it using RLE, and returns the compressed string. Case matters - uppercase and lowercase characters should be considered distinct. You may assume that there are no digit characters in the input string. There are no other restrictions on the input - it may contain spaces or punctuation. There is no need to treat nonletter characters any differently from letters.

Answer 1

Markers□ Properties妃Servers膼Data Source Explorer Snippets 貝 terminated> Compression Java Application] C:AProgram Files Javaljre1.8.0_731binljavaw.exe (Nov 8, 2016, 8:33:38 AM) Enter a string for compression: Console 3 ErTTT After applying RLE algorithm, this string is converted into: q9w5e2rt5y4qw2Er3T

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import java.util.Scanner;

public class Compression {

   // Method to compress string
   public static String compress(String original) {

       String compressedString = "";

       // Iterate over string character by character
       for (int i = 0; i < original.length(); i++) {

           char currentChar = original.charAt(i);

           int currentCharCount = 1;

           // Check for the next all characters which are equal to current
           // character
           while ((i + 1) < original.length() && original.charAt(i) == original.charAt(i + 1)) {
               currentCharCount++;
               i++;
           }

           // if currentCharCount >1 means compress applies
           if (currentCharCount > 1) {
               compressedString = compressedString + String.valueOf(currentCharCount) + String.valueOf(currentChar);
           } else {
               compressedString = compressedString + String.valueOf(currentChar);
           }

       }

       return compressedString;
   }

   public static void main(String[] args) {

       Scanner sc = new Scanner(System.in);

       // Read original string from user
       System.out.println("Enter a string for compression: ");
       String original = sc.next();

       // Call compress function
       String compressedString = compress(original);

       // Display compressed string
       System.out.println("After applying RLE algorithm,this string is converted into:\n" + compressedString);

       // close stream
       sc.close();
   }

}