Count and Say

The count-and-say sequence is the sequence of integers beginning as follows:

1, 11, 21, 1211, 111221, ...

• 1 is read off as "one 1" or 11.
• 11 is read off as "two 1s" or 21.
• 21 is read off as "one 2, then one 1" or 1211.

Given an integer n, generate the nth sequence.
Note: The sequence of integers will be represented as a string.

Java

public class Solution {
    public String countAndSay(int n) {
        if(n <= 0) {
            return "";
        }

        String s = "1";
        int count = 1;

        for(int i = 1; i < n; i++) {
            StringBuilder temp = new StringBuilder();
            for(int j = 0; j < s.length(); j++) {
                if(j + 1 < s.length() && s.charAt(j) == s.charAt(j + 1)) {
                    count++;
                } else {
                    temp = temp.append(count).append(s.charAt(j));
                    count = 1;
                }
            }
            s = temp.toString();
        }
        return s;
    }
}