leetcode week18

Count and Say

The count-and-say sequence is the sequence of integers with the first five terms as following:

1.     12.     113.     214.     12115.     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.

class Solution {public:    string countAndSay(int n) {        if(n==1) return "1";                string str = countAndSay(n-1)+'*';                int count = 1;        string out="";        for(int i=0;i<str.size()-1;i++)        {            if(str[i] == str[i+1]) count++;            else            {                stringstream s;                s << count;                out = out+s.str()+str[i];                count=1;            }        }        return out;    }};