题解 | #验证IP地址#

using System;
using System.Collections.Generic;
using System.Linq;


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
        if(IP.Contains('.')){
            string[] nums = IP.Split('.');
            if (nums.Length != 4) return "Neither";
            foreach(string str in nums){
                if(int.TryParse(str, out int num)){
                    if(0 < num && num < 256 && str[0] != '0') continue;
                    else if(num == 0 && str.Length == 1) continue;
                }
                return "Neither";
            }
            return "IPv4";
        }
        else if(IP.Contains(':')){
            string[] nums = IP.Split(':');
            if (nums.Length != 8) return "Neither";
            foreach(string str in nums){
                if(str.Length <= 4 && str.Length > 0){
                    foreach(char c in str){
                        if((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f'))
                        continue;
                        return "Neither";
                    }
                }
                else return "Neither";
            }
            return "IPv6";
        }
        return "Neither";
    }
}