Run Length Encoding | Programming In Java

 Given a string, Your task is to complete the function encode that returns the run-length encoded string for the given string.

eg if the input string is “wwwwaaadexxxxxx”, then the function should return “w4a3d1e1x6″.
You are required to complete the function encode that takes only one argument the string which is to be encoded and returns the encoded string.

Example 1:

Input:
str = aaaabbbccc
Output: a4b3c3
Explanation: a repeated 4 times
consecutively b 3 times, c also 3
times.

Example 2:

Input:
str = abbbcdddd
Output: a1b3c1d4

Your Task:
Complete the function encode() which takes a character array as an input parameter and returns the encoded string.

Expected Time Complexity: O(N), N = length of a given string.
Expected Auxiliary Space: O(1)

Constraints:
1<=length of str<=100

Solution:

import java.util.*;

 

class RLEncoding

{

   public static void main(String[] args) 

   {

 

      Scanner sc = new Scanner(System.in);

    

  int T = sc.nextInt();

  sc.nextLine();

  while(T>0)

  {

  

String str = sc.nextLine();

RLE g = new RLE();

System.out.println(g.encode(str));

      

        T--;

  }

   }

}

// } Driver Code Ends

class RLE

 {

String encode(String str)

{

    int length = str.length();

    int i=0;

    char letter = str.charAt(i);

    int counter=1;

    String newString=""+letter;

    

    for(i=1;i<length;i++){

        if(letter!=str.charAt(i)){

            letter=str.charAt(i);

            newString = newString+counter+letter;

            counter=1;

        }else{

            counter++;

        }

    }

    return newString+counter;

          //Your code here

}

 }