I am trying to figure out what the time complexity is for a Look and Say sequence generator which receives an integer n and outputs the nth term in the look and say sequence.I'm looking at the below code. It is a tail recursion, but I can't get the summation properly. Can someone please provide an explanation along with the answer?string LookAndSay(int n){    string ret;    if(n == 0)    {        return 1;     }    string s = LookAndSay(n-1);    for(auto it = s.begin(); it != s.end(); it++)    {        char curDigit = *it;        int count = 0;        while(it != s.end() && *it == curDigit)        {            count++;            it++;        }        it--;        std::stringstream ss;        ss << count;        ret += ss.str();        ret += curDigit;    }    return ret;}
Runtime of Look and Say
algorithm analysis;runtime analysis;recursion