Count and Say

Count and Say.py

class Solution:
    def countAndSay(self, n):
        """
        :type n: int
        :rtype: str
        """
        s = '1'
        for i in range(1, n):
            s = self.cal(s)
        
        return s 
        
    def cal(self, s):
        cnt = 1 
        length = len(s)
        ans = ''
        for i, c in enumerate(s):
            if i+1  < length and s[i] != s[i+1]:
                ans = ans + str(cnt) + c
                cnt = 1
            elif i+1 < length:
                cnt = cnt + 1 
                
        ans =ans + str(cnt) + c 
        return ans