content: package LeetCode.Easy.CountAndSay;
  
  /*
  38. Count and Say
  
  The count-and-say sequence is a sequence of digit strings defined by the recursive formula:
  
  countAndSay(1) = "1"
  countAndSay(n) is the way you would "say" the digit string from
  countAndSay(n-1), which is then converted into a different digit string.
  To determine how you "say" a digit string, split it into the minimal number of groups so that each group is a contiguous section all of the same character. Then for each group, say the number of characters, then say the character. To convert the saying into a digit string, replace the counts with a number and concatenate every saying.
  
  For example, the saying and conversion for digit string "3322251":
  
  Given a positive integer n, return the nth term of the count-and-say sequence.
  
  
  Example 1:
  Input: n = 1
  Output: "1"
  Explanation: This is the base case.
  
  Example 2:
  Input: n = 4
  Output: "1211"
  Explanation:
  countAndSay(1) = "1"
  countAndSay(2) = say "1" = one 1 = "11"
  countAndSay(3) = say "11" = two 1's = "21"
  countAndSay(4) = say "21" = one 2 + one 1 = "12" + "11" = "1211"
  
  
  Constraints:
  1 <= n <= 30
  */
  
  public class Solution {
    public String countAndSay(int n) {
      if (n == 1) return "1";
  
      // String res = countAndSay(n - 1);
      // int i = 2;
  
      // while (i <= n) {
      //   int count = 1;
      //   String temp = "";
  
      //   for (int j=0; j<res.length()-1; ++j) {
      //     if (res.charAt(j) == res.charAt(j+1))
      //       ++count;
      //     else {
      //       temp += count + "" + res.charAt(j);
      //       count = 1;
      //     }
      //   }
      //   temp += count + "" + res.charAt(res.length()-1);
      //   res = temp;
      //   ++i;
      // }
  
      String temp = countAndSay(n - 1);
  
      String res = "";
      int count = 1;
  
      for (int i = 0; i < temp.length() - 1; ++i)
        if (temp.charAt(i) == temp.charAt(i + 1)) ++count;
        else {
          res += count + "" + temp.charAt(i);
          count = 1;
        }
  
      res += count + "" + temp.charAt(temp.length() - 1);
  
      return res;
    }
  
    public static void main(String[] args) {
      Solution solution = new Solution();
  
      // should be 1211
      System.out.println(solution.countAndSay(4));
    }
  }
  