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

1.     1
2.     11
3.     21
4.     1211
5.     111221

哈哈，轉移到國際版了。這道題的意思是 1 = “1”，從1開始往後的字串都是指前面一個字串按順序出現的值得計數形式。

python：

class Solution(object):
    def countAndSay(self, n):
        """
        :type n: int
        :rtype: str
        """
        res = "1"
        if n == 1:
            return res
        for i in range(1,n):
            j = 0
            count = 1
            temp = ""
            while j < len(res):
                s = res[j]
                if j == len(res) - 1:
                    temp += str(count)
                    temp += s
                    break
                if res[j] == res[j+1]:
                    count += 1
                    j += 1
                else:
                    temp += str(count)
                    temp += s
                    count = 1
                    j += 1
            res = temp
        return res
 

C++： 

class Solution {
public:
    string countAndSay(int n) {
        string res = "1";
        if(n == 1) return res;
        for(int i = 1;i < n;i++){
            int j = 0;
            int count = 1;
            string temp;
            while(j < res.length()){
                char s(res[j]);
                if(j == res.length() - 1){
                    temp += to_string(count);
                    temp += s;
                    break;
                }
                if(res[j+1] == res[j]){
                    count += 1;
                    j += 1;
                }
                else{
                    temp += to_string(count);
                    temp += s;
                    count = 1;
                    j += 1;
                }
            }
            res = temp;
        }
        return res;
    }
};