题解 | #数字字符串转化成IP地址#

class Solution:
    def restoreIpAddresses(self , s: str) -> List[str]:
        # write code here
        n = len(s)
        ip_list =[]
        if n<4 or n >12:
            return []
        for i in range(1,n):
            for j in range(i+1,n):
                for k in range(j+1,n):
                    str1 = list(s)
                    str1.insert(k,'.')
                    str1.insert(j,'.')
                    str1.insert(i,'.')
                    str1=''.join(str1)
                    if self.isip(str1):
                        ip_list.append(str1)
        return ip_list
    def isip(self,ip):
        ip = ip.split('.')
        bool =True
        if len(ip) !=4:
            bool = not bool
            return bool
        else:
            for i in ip:
                iv = int(i)
                if iv>255:
                    bool = not bool
                    return bool
                if len(i)>=2 and i[0]=='0':
                    bool = not bool
                    return bool
            return bool