count and say

public class Solution {
    public String countAndSay(int n) {
            StringBuilder curr=new StringBuilder("1");
            StringBuilder prev;
            int count;
            char say;
            for (int i=1;i<n;i++){
                prev=curr;
                curr=new StringBuilder();       
                count=1;
                say=prev.charAt(0);
                
                for (int j=1,len=prev.length();j<len;j++){
                    if (prev.charAt(j)!=say){
                        curr.append(count).append(say);
                        count=1;
                        say=prev.charAt(j);
                    }
                    else count++;
                }
                curr.append(count).append(say);
            }                   
            return curr.toString();
        
    }
}