Leetcode38. 外观数列

题目传送地址: ​​https://leetcode.cn/problems/count-and-say/​​

代码如下

//递归解法
 public static String countAndSay(int n) {
        if (n == 1) {
            return "1";
        }
        String s = countAndSay(n - 1);
        int left = 0;
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < s.length() + 1; i++) {
            char c = s.charAt(left);
            if (i == s.length()) {
                stringBuilder.append(i - left).append(c);
                break;
            }
            char c1 = s.charAt(i);
            if (c != c1) {
                int count = i - left;
                stringBuilder.append(count).append(c);
                left = i;
            }
        }
        return stringBuilder.toString();
    }