1. 题目

The count-and-say sequence is the sequence of integers beginning as follows:

1 is read off as "one 1" or 11.

Note: The sequence of integers will be represented as a string.

2. 思路

迭代重复即可

3. 代码

耗时：3ms

#include 
    
     class Solution {public:    string countAndSay(int n) {        string s = "1";        while (--n != 0) {            s = foo(s);        }        return s;    }        string foo(string& s) {        string ret;        int len = s.length();        if (len == 0) {return ret;}        char last = s[0];        int cnt = 1;        stringstream ss;        for (int i = 1; i < len; i++) {            if (s[i] != last) {                ss << cnt << last;                last = s[i];                cnt = 1;            } else {                cnt++;            }        }        ss << cnt << last;        return ss.str();    }};