题解 | #验证IP地址#

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;


class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 验证IP地址
     * @param IP string字符串 一个IP地址字符串
     * @return string字符串
     */
    public string solve (string IP) {
        // write code here
        var ipv4 = @"^((2(5[0-5]|[0-4]\d))|[1]?\d{1,2})(\.((2(5[0-5]|[0-4]\d))|[1]?\d{1,2})){3}$";
        var ipv6 = @"^(?:[0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}$";
        return Regex.IsMatch(IP, ipv4) ? "IPv4" : Regex.IsMatch(IP,
                ipv6) ? "IPv6" : "Neither";
    }
}