python写算法题：leetcode: 38. Count and Say

class Solution(object):
    def countAndSay(self, n):
        """
        :type n: int
        :rtype: str
        """
        if n==1: return "1"
        ret=self.countAndSay(n-1)
        lastc=0
        lastcnt=0
        out=""
        for c in ret:
            if c==lastc or lastcnt==0:
                lastcnt+=1
                lastc=c
            else:
                out+="%d%c"%(lastcnt,lastc)
                lastcnt=1
                lastc=c
        out+="%d%c"%(lastcnt,lastc)
        return out