AC代碼：

class Solution(object):    def repeatedSubstringPattern(self, str):        """        :type str: str        :rtype: bool        """        for i in range(1,len(str)/2+1):            if len(str)%i != 0:                continue            if self.issubstring(str,i):                return True        return False    def issubstring(self,str,i):        tmp = str[:i]        for j in range(i,len(str),i):            if tmp != str[j:j+i]:                return False        return True
思路：從1到length/2長度依次進行判斷，發現滿足情況的substring即可返回True.