Leetcode38 外观数组题解

这种字符串处理的题目，微软很喜欢考

思路是在递归的基础上进行字符串处理

1class Solution {
2    public String countAndSay(int n) {
3        if(n==1) return "1";
4        String str = countAndSay(n-1);
5        StringBuilder sb = new StringBuilder();
6        int count = 1, i = 0;
7        while(i<str.length()){
8            while(i+1<str.length()&&str.charAt(i)==str.charAt(i+1)){
9                count++;
10                i++;
11            }
12            sb.append(count);
13            sb.append(str.charAt(i));
14            i++;
15            count = 1;
16        }
17        return sb.toString();
18    }
19}