CountAndSay.java

class CountAndSay {
 public String countIdx(String s){
 StringBuilder sb = new StringBuilder();
 char c = s.charAt(0);
 int count = 1;
 for(int i = 1; i < s.length(); i++){
 if(s.charAt(i) == c){
 count++;
 }
 else
 {
 sb.append(count);
 sb.append(c);
 c = s.charAt(i);
 count = 1;
 }
 }
 sb.append(count);
 sb.append(c);
 return sb.toString();
 }
 
 public String countAndSay(int n) {
 String s = "1";
 for(int i = 1; i < n; i++){
 s = countIdx(s);
 }
 return s;
 }
}