leetcode-----38. 外观数列

• 链接：https://leetcode-cn.com/problems/count-and-say/

代码

class Solution {
public:
    string countAndSay(int n) {
        string ans = "1";
        for (int i = 0; i < n - 1; ++i) {
            string s;
            for (int j = 0; j < ans.size();) {
                int k = j + 1;
                while (k < ans.size() && ans[k] == ans[j]) k++;
                s += to_string(k - j) + ans[j];
                j = k;
            }
            ans = s;
        }
        return ans;
    }
};