Java compressing Strings

Question

I need to create a method that receives a String and also returns a String.

Ex input: AAABBBBCC

Ex output: 3A4B2C

Well, this is quite embarrassing a

Answer 1

In the count=... line, lastIndexOf will not care about consecutive values, and will just give the last occurence.

For instance, in the string "ABBA", the substring would be the whole string.

Also, taking the length of the substring is equivalent to subtracting the two indexes.

I really think that you need a loop. Here is an example :

public static String compress(String text) {
    String result = "";

    int index = 0;

    while (index < text.length()) {
        char c = text.charAt(index);
        int count = count(text, index);
        if (count == 1)
            result += "" + c;
        else
            result += "" + count + c;
        index += count;
    }

    return result;
}

public static int count(String text, int index) {
    char c = text.charAt(index);
    int i = 1;
    while (index + i < text.length() && text.charAt(index + i) == c)
        i++;
    return i;
}

public static void main(String[] args) {
    String test = "AAABBCCC";
    System.out.println(compress(test));
}