Count and Say LeetCode:Mysolution

Count and Say

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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.\

public class Solution {    public String countAndSay(int n) {    if (n <= 0) {    return "";    }    return countSubString(n);    }    String countSubString(int n) {        if (n == 1) {        String s = "1";            return s;        }        String thisN = countSubString(n - 1);        char temp = thisN.charAt(0);        int count = 0;        StringBuffer levelRes = new StringBuffer();        for (int i = 0; i < thisN.length(); i++) {            if (temp == thisN.charAt(i)) {                count++;            } else {                levelRes.append(count);                levelRes.append(temp);                temp = thisN.charAt(i);                count = 1;                            }        }        levelRes.append(count);        levelRes.append(temp);        return levelRes.toString();    }}