[LeetCode] CountAndSay

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 n^th sequence.
Note: The sequence of integers will be represented as a string. 

注意最后的一个count不能忘记

Java code:

 public String countAndSay(int n) {
        String s = "1";
        int i = 1;
        
        while(i < n){
            int j = 0;
            char a = s.charAt(0);
            int count = 0;
            String nexts = "";
            
            while(j < s.length()){
                if(s.charAt(j) == a){
                    count++;
                    j++;
                }else{
                   nexts += count + String.valueOf(a);
                   a = s.charAt(j);
                   count = 0;
                }
            }
            
            nexts += count + String.valueOf(a);//the last part
            
            s = nexts;
            i++;
        }
        
        
        return s;
    }