leet_0038_look_and_say___aoc.cpp

class Solution {
public:
    string countAndSay(int n)
    {
        return counting(n);
    }

    string  counting(int n)
    {
        deque<int>      dq;
        string          res, temp_outer_loop, temp_inner_loop;
        int             count, len, i;

        if (n == 1)
            return "1";
        res = "11";
        while (--n > 1)
        {
            len = res.length();
            count = 1;
            i = 0;
            temp_outer_loop = "";
            while (i < len)
            {
                temp_inner_loop = "";
                if (i + 1 < len && res[i] == res[i + 1])
                {
                    count += 1;
                    i += 1;
                }
                else if (i + 1 == len || (i + 1 < len && res[i] != res[i + 1]))
                {
                    temp_inner_loop += count + '0';
                    temp_inner_loop += res[i];
                    count = 1;
                    i += 1;
                }
                
                temp_outer_loop += temp_inner_loop;
            }
            res = temp_outer_loop;
            cout << "n = " << n << "\ncurrent step = " << res << "\n";
        }
        return res;
    }
};

/*

1   1
2   11
3   21
4   1211
5   111221
6   312211
7   13112221
8   1113213211
9   31131211131221
10  13211311123113112211



*/