Java compressing Strings

compression, java, loops, string

Solution

Loop through the string remembering what you last saw. Every time you see the same letter count. When you see a new letter put what you have counted onto the output and set the new letter as what you have last seen.

String input = "AAABBBBCC";

int count = 1;

char last = input.charAt(0);

StringBuilder output = new StringBuilder();

for(int i = 1; i < input.length(); i++){
    if(input.charAt(i) == last){
    count++;
    }else{
        if(count > 1){
            output.append(""+count+last);
        }else{
            output.append(last);
        }
    count = 1;
    last = input.charAt(i);
    }
}
if(count > 1){
    output.append(""+count+last);
}else{
    output.append(last);
}
System.out.println(output.toString());

Problem

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 and I couldn't manage to do it on the interview that I had today ( I was applying for a Junior position ), now, trying at home I made something that works statically, I mean, not using a loop which is kind of useless but I don't know if I'm not getting enough hours of sleep or something but I can't figure it out how my for loop should look like. This is the code: ``` public static String Comprimir(String texto){ StringBuilder objString = new StringBuilder(); int count; char match; count = texto.substring(texto.indexOf(texto.charAt(1)), texto.lastIndexOf(texto.charAt(1))).length()+1; match = texto.charAt(1); objString.append(count); objString.append(match); return objString.toString(); } ``` Thanks for your help, I'm trying to improve my logic skills.

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