Counting Characters only if they are right next to each other

Question

How to count the characters only if they are right next to each other, otherwise just print the characters as they are. I wrote the following code based on my little knowledge of Java.

for example String w="kjiikkkjial";

the result should be: kji2k3jial

    String am ="asbbaamkkkjkssg";
    char op = 0;

    char[] ch = am.toCharArray();
    for(int i=0; i<ch.length; i++) {
        int k=1;
        for(int j=i+1; j<ch.length; j++) {
            if(ch[i]==ch[j]) {
               k++;
               op=ch[j];    
               i=j;
            }
            else  break;
        }
        if(k>1)
            System.out.print(op+""+k);
        else
            System.out.print(ch[i]);    
    }

"How to do _xyz_ ?" => By writing code! If you did and got stuck, then show us your attempts and explain what exact problems you have. — Seelenvirtuose, Sep 08 '18 at 08:37
What you want is run-length encoding. What have you tried (do you know how to append a number to a string? compare two chars? index a string? etc.)? — user202729, Sep 08 '18 at 08:37
Looks like a duplicate. This might be your answer: https://stackoverflow.com/questions/11442162/java-run-length-encoding — Komiii, Sep 08 '18 at 08:44
@Selenvirtuose, sorry i forgot to add the code, now i have.. — LaterHomie, Sep 08 '18 at 08:49
@komiii its not same, there string is compose of just duplicate characters. — LaterHomie, Sep 08 '18 at 08:51

score 0 · Accepted Answer · answered Sep 08 '18 at 09:02

0

This should work, call this function with the input as your string and it will return the expected output.

public static String runLengthEncoding(String text) {
    String encodedString = "";

    for (int i = 0, count = 1; i < text.length(); i++) {
        if (i + 1 < text.length() && text.charAt(i) == text.charAt(i + 1))
            count++;
        else {
            encodedString = encodedString.concat(Character.toString(text.charAt(i)));
            if(count>1) {
                encodedString = encodedString.concat(Integer.toString(count));
            }
            count = 1;
        }
    }
    return encodedString;
}

This is a link to the working example on ideone.

answered Sep 08 '18 at 09:02

Mukesh A

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my code is working too, can you please tell what is wrong with my logic? – LaterHomie Sep 08 '18 at 09:07
you are using 2 loops, first to iterate over the string, without comparing, and the second loop to compare, which you could have at the same place like what I have done in my answer, the solution may be correct but it's not efficient. – Mukesh A Sep 08 '18 at 09:12

Counting Characters only if they are right next to each other

1 Answers1