leetcode 394. 字符串解码

class Solution(object):
    def decodeString(self, s):
        reStr=''
        searchObj=re.search( r'(\d+)\[(\w+)\]', s)
        if searchObj == None:
            return s 
        if searchObj!=None:
            tmpStr=searchObj.group()
            zifu =searchObj.group(2)
            xishu=searchObj.group(1)
            start_pos=s.find(tmpStr,0,len(s))
            pinjieStr=self.pinjie(zifu,xishu)
            allpinjie=s[0:start_pos]+pinjieStr+s[start_pos+len(tmpStr):]
            return self.decodeString(allpinjie)
    def pinjie(self,target,num):
        tmp=''
        for i in range(0,int(num)):
            tmp+=target
        return tmp